Vaginal Birth After 2 or More Cesareans

by KMom

Copyright 2000-2001 KMom@Vireday.Com. All rights reserved.

DISCLAIMER: The information on this website is not intended and should not be construed as medical advice. Consult your health provider.




Is trying for a Vaginal Birth After Cesarean (VBAC) a reasonable option after you've had 2 (or more) cesarean sections?  Most authors conclude that it is, but many OBs are reluctant to consider it, especially recently due to a VBAC backlash movement.  Because many doctors have been reluctant to consider it, most medical literature and collections of VBAC stories have concentrated on VBAC after 1 cesarean (VBA1C).  There is an urgent need for information, analysis of medical literature, and stories of VBAC after multiple cesareans (VBA2+C).  

This websection analyzes the medical literature on the subject, the chances of success, the risk of rupture, and the emotional issues that may be involved, hints for healing, etc. There is another websection (VBA2+C Stories FAQ) that relates personal stories of VBAC after multiple cesareans.  It mostly contains personal VBA2+C stories others have decided to share, but it also has resources for finding VBA2+C stories in books and online. The VBA2+C FAQ and the VBA2C Stories FAQ are meant to be complementary and should be considered together. 

Readers are urged to do their own research in order to reasonably evaluate the various factors in VBAC vs. elective repeat c-section decisions.  There are many factors to consider in deciding.  Excellent VBAC information can be found online; readers are directed to the resources at,, and the many medical journal abstracts available online at  Be sure you understand what you are reading and the potential biases of the writers!  

Other valuable resources include the following books:

Further resources can be found in the References section of the VBA2+C Stories FAQ, as well as in the websection Great VBAC Resources on this site.



The purpose of this FAQ is not to convince you that VBA2C is or is not the right option for you.  It is simply to gather together in one place more information about the difficult-to-find subject of VBA2C, and to explore its various issues, both medical and personal.   It is a detailed look at the research on VBA2C, an examination of the critical issues in the controversy, what research and anecdotal evidence shows on these issues, and important considerations if you do select a trial of labor.  It is not a short or quick introduction to the subject, so set aside some time for reading it thoroughly.  

It's important to remember that this is simply a sharing of information by and for health consumers.  Kmom is not an expert, not a professional researcher, not a medical professional, and she does not offer medical advice.  Although she has felt free to add in her opinions in the discussions of various VBAC controversies, these are certainly NOT medical advice, and are added simply for discussion's sake.  Readers should always be very cautious about any health information they get online (or indeed, anywhere else!).  Remember, YOU are the one ultimately responsible for your own healthcare decisions.  Be thorough in your researching, discuss the issues with your healthcare providers, and explore all your options before making decisions.  The purpose of this FAQ is not to offer medical advice.

Kmom is not entirely unbiased on the issue of VBACs; she has had 2 cesareans and then a VBA2C herself.  It was her search for information about the benefits and risks of a trial of labor after multiple cesareans that led to the creation of this FAQ.  However, although Kmom tends to favor VBACs and shares her opinions on this in this FAQ, she has tried to clearly label her opinions as such, and has tried to represent all sides of the VBAC issue fairly.  She strongly feels that each woman must consult her provider, look at the research for herself, examine her own birthing priorities and circumstances, and then decide for herself what is best in her situation. No criticism of either choice of birth mode should be inferred. 

The focus in this websection is primarily on VBAC after 2 c-sections because that is what most of the medical literature deals with and because few women with 3+ c-sections are given the opportunity to even try a VBAC.  However, that does not mean that VBAC after more than 2 c/s is inappropriate, impossible, or has never happened.  In fact, quite a number of women have had VBACs after 3 or more cesareans (VBA3+C).  Unfortunately, it's not well-studied in the literature, and official study sizes are small (although there is some data, which is presented here).  Therefore, most of the information in this FAQ will necessarily deal more directly with VBA2C, but whenever specifics are available on VBAC after 3 or more c/s they are given, and these stories are also included on the VBA2+C Stories FAQ.  

Finally, Kmom would particularly like to note that she strongly dislikes the terms, "Trial of Labor" (or the British alternative, "Trial of Scar") and "Attempted VBAC".  It implies being on trial, a pass-fail 'test', a judgment, a tentative attempt.  Kmom's personal opinion is that a labor after previous cesarean should be viewed and treated like any other labor. Kmom particularly dislikes the terms "failed trial of labor/failed VBAC".  This is NOT a failure.  However, this is the terminology used by the medical studies reviewed in this FAQ, and often even in VBAC books.  Alternative terminology is cumbersome and not standard, so Kmom has reluctantly utilized these terms in this FAQ.  Readers should be aware that its usage herein does not constitute approval!  Words can matter, and obstetrics is full of misogynistic and condescending terms as it is.  We can use these terms for ease of use and because it is standard, but we should also be aware of the weaknesses and subtle underlying implications of it.


Terms and Abbreviations

Reading a Frequently Asked Questions list (FAQ) about childbirth issues is often like negotiating a minefield full of unfamiliar terms and abbreviations.  Because it was not practical to write out each term each time, the following is a brief guide to the terms and abbreviations you might see in these particular FAQs.   


Table of Studies

The following are the main VBA2+C studies available.  Details are included from the full paper on the study, except in the cases where the original is not in English, in which case information from the abstract is used instead.  Not all studies offer full information in every category, so some columns are left blank.  A few studies had typos or inconsistent statistics; these are indicated with a "?".  

The table is limited to studies that were done after about 1979 because before then authors often mixed low transverse incisions in with classical incisions, thus obscuring the risk.  Also, laboring conditions and protocols were so different then that comparisons are difficult.  Too many of those studies involve women with classical cesareans (which have a higher rupture rate), heavy use of drugs, forceps, and other highly interventive protocols which obscure the data.  Therefore, only studies under more 'modern' laboring conditions were used so comparisons would be more valid.  

Be aware, though, that even some of these 'modern' laboring conditions are rather questionable and may have impacted VBAC success rates and rupture rates.  Studies done in the 80s tended to have great restrictions on laboring moms, including mandatory IVs, internal monitoring, Internal Uterine Pressure Catheters (IUPCs), flat-on-back labor position and stirrups for pushing, sometimes urinary catheters, and strict adherence to very rigid labor curves.  They tended to have lower and much more cautious use of oxytocin and other induction agents.  

Studies in the 90s, on the other hand, tended to loosen up many of the uptight restrictions on VBAC moms from the 80s, but used oxytocin and other very strong labor drugs for induction and augmentation much more freely.  Now that the new century is here, oxytocin and other drug use is being looked at with more caution, since some studies suggest its overuse can strongly increase rupture rates.  So although these modern studies are more comparable than studies from before 1979, they still cannot be compared exactly, since labor protocols vary greatly between facilities and evolve over time. 

Here are the major VBAC studies with VBA2+C data in them that were used for this FAQ. 

Table I: VBA2C Studies

Study Journal Year VBA2C Success Rate Rupture Rate Induction/ Augmentation Used?  Sample Size Favor VBA2C? Comments                          
Saldana LR et al.  Am J Ob-Gyn 1979 58%VBA2+C  rate 0.0% in TOL group rarely n=38 yes Records 22 VBA2+Cs, including 4 VBA3Cs
Porreco, RP and Meier PR J of Reprod Med 1983 81%VBA2+C rate 0.0% ruptures or dehiscences yes, 33% had oxytocin n=21 yes 7 of 9 who had previous c/s for CPD had a VBAC
Martin, JN et al. Am J Ob-Gyn 1983 63%VBA2+C rate 0.0% ruptures or dehiscences yes n=19 yes 9/13 VBA2C (69%)  and 3/6 VBA3+C (50%)
Wadhawan, S and Narone, JN Intl J Gyn Ob 1983 71% VBA2C rate apparently 0.0% ruptures rarely, 4% induced and 2% augment. n=31 yes 319 women had a TOL, 31 of whom had 2 prior cesareans.  22/31 had VBA2Cs.  5 women with 'impending ruptures' were rushed to surgery (including 2 with 2 prior c/s) but apparently nothing was found because study states there were no ruptures.
Phelan, JP et al. Am J Ob-Gyn 1987 Overall, 73% VBA2+c rates

82% VBA1C, 72% VBA2C, 90% VBA3C

0.3% true rupture overall; multiple cesareans did not increase rate of dehiscence or rupture  yes, nearly 50% received pitocin, mostly for augmentation n=1796 overall; n=159 in VBA2+C TOLs


yes dehiscence and rupture rates were the same or statistically similar  in TOL and ERCS groups; multiple cesareans did not have higher rates of dehiscences or ruptures 
Farmakides, G et al. Am J Ob-Gyn 1987 77% VBA2+C overall 0.0% ruptures, 1 dehiscence yes, in 5 women (9%) n=57 yes 18/57 had 3 previous c/s, but does not specify success rates separately
Stovall, TG et al. Ob-Gyn 1987 84% VBA2+C overall 0.0% ruptures in multiple c/s group yes n=51 yes 79.5% VBA2C and 100% VBA3C in low transverse scars; 100% VBA2C and 100% VBA3C in low vertical scars
Pruett, KM et al.  Ob-Gyn 1988 45% VBA2+C overall

45% VBA2C, 50% VBA3C 

no ruptures, 5.5% scar dehiscence, all in the group that received pitocin yes, 55% received pitocin n=55 yes 42 with 'unknown scar', 11 low transverse scar, 2 with  low-vertical scars

oxytocin augment=30% VBAC; no oxytocin augmentation had 64% success rate (double the VBAC rate!)

Flamm, BL et al. Am J Ob-Gyn 1988 74% VBAC overall

76% VBA2C, 71% VBA3C

0.0% ruptures or dehiscences yes, 1/4 received pitocin n=89 women with 2+ prior c/s; n=1776 overall TOLs yes 82 TOLs in women with 2 prior c/s, and 7 TOLs in women with 3 prior c/s.  
Novas, J et al.  Am J Ob-Gyn 1989 80% overall VBA2+C; 78% VBA2C and 89% VBA3+C no ruptures in women with multiple lower transverse scars yes, almost half were induced with pitocin n=36 yes 80% success for 2 or more previous c/s

There was one rupture in a woman with two previous classical scars who was also given pitocin augmentation

Veridiano, NP et al. Int J Gyn OB 1989 78% success overall; ~84% success after 2+c/s 2 ruptures for 1% rate; unspecified whether these were in women with 1 or 2+ cesareans yes, but low rate (10 pts.) n=25? for 2+ c/s yes The statistics in this study do not all add up correctly

14 VBA2Cs, 4 VBA3Cs, 2 VBA4Cs, 1 VBA5C.  

Phelan, JP et al. Ob-Gyn 1989 69% VBA2C 0.0% true ruptures in TOL group (0.2% ERCS group); 1.8% scar sprtn. in TOL; in ERCS, 4.6% yes, 57% had pitocin used, mostly augmentation n=501 TOL in women w/ 2 prev. c/s yes dehiscence w/ pitocin  2.1% vs. 1.4% w/out pitocin; pitocin also significantly lowered VBAC success rates.  During study, pitocin rate increased from 22% to 57% but VBAC rate did not improve
Flamm, BL et al. Ob-Gyn 1990 64% success after 2+ c/s uterine rupture rate not higher  in those  with multiple c/s yes, in overall VBAC study 68% had pitocin n=156 in second half of study yes 5-year multicenter study of VBACs; 245 of 5733 TOLs were in women with 2+C.  89 of these were reported in the Flamm 1988 study, leaving 156 new ones to add to these totals here. Totals here reflect only this second half of study
Hansell,RS et al.  Birth 1990 77% overall; 

79% VBA2C

60% VBA3C

100% VBA4C 

   0.0% ruptures in TOL group  no n=35 TOL yes small study, over 5 years

no increase in maternal or fetal morbidity or mortality

women with trial of labor had fewer postpartum complications and shorter hospital stays

Wessel, J et al.   Z. Geburt. Perinatal. 1990 75% success rate ? unknown n=16 yes very small study

"The justifications for a repeated primary cesarean section based on the previous record to two or more cesarean sections alone seems to be no longer given."

Leung, AS et al Am J Ob-Gyn 1993 unknown, this was a rupture study 2% rupture rate for 2-3 prior c/s; 0.82% rupture overall for all VBACs

risk ratio for rupt. w/ 2+ c/s = 2.6x; after adj. for variables risk=3.8x

77% of ruptures had had pitocin, usually in very early labor; use of pitocin had a 2.4x increased risk for rupture  

n=70 (total study had 8513 TOL pts; examined 70 that ruptured)

unclear, prob. yes with care VBAC moms augmented with pitocin aggressively even in early labor, more than pts. w/out prior c/s  

Authors point out that although 2% of women with 2+ c/s had ruptures, 98% still did not have ruptures

Chattopadhyay, SK  et al.   Br. J. Ob-Gyn 1994 90% success rate 0.0% rupture; dehiscence 1/115 or  0.8% yes, 1/3 with PGE2, pit if needed for augmentation n=115 TOL

n=1006 ERCS

yes Saudi study; rupture rate same as in group with ERCS

no scar dehiscence, no real effect on VBAC success rates in group induced or augmented

Cowan, RK et al. Ob-Gyn 1994 81% overall VBAC rate

79% VBA2+C rate overall

77% VBA2C, 100% VBA3C

overall, 5/593=0.8%

1/72=1.4% after 2+c/s (unknown scar)

yes, 39% pitocin use (11% indctn, 28% augmntn) n=593 overall

n=72 TOL after 2 c/s

n=3 TOL after 3 c/s

yes 518 TOL after 1 c/s, 72 after 2 c/s, 3 after 3 c/s (therefore 75 after 2+ c/s)

1 rupture in 2 prior c/s group; pt. had 'unknown' scar so it's possible it might have been a classical scar

Behrens O, et al. Geburt. Frauen. 1994 85% VBAC overall

70% VBA2C

0.5% for entire group (induction study) yes, entire group was induced unknown number with 2 prior cesareans probably yes original study in German; abstract is not clear about the VBA2C aspects of the study except for 70% VBA2C rate in the group induced with prostaglandin E2 gel
Granovsky-Grisaru, S. et al. J Perinat Med 1994 73% success rate 0.0% yes, 54% had oxytocin augmentation n=26 yes "maternal complication rate was lower than that of the control group" [ERCS group]
Miller, DA et al. Ob-Gyn 1994 75% VBA2+C overall; 

83% VBA1C, 75% VBA2C, 79% VBA3+C

rupture rate: 0.6% 1 c/s, 1.7% 2+ c/s

(1.8% 2 c/s, 1.2% 3+ c/s)

yes, but did not control for pitocin use n=1827 TOL after 2+ c/s; 10 year study yes, but only for those highly motivated for VBA2C biggest VBA2C study

rupture rate was 3x higher for those with 2 or more c/s when averaging 2 and 3+ previous c/s together (see comments under references section)

Asakura H. et al. Ob-Gyn 1995 64% VBA2+C rate 1% true rupture rate, TOL group yes, 'liberally' n=302 yes dehiscence slightly higher in multiple c/s group but did not reach statistical significance
Davies, GAL et al.  J Reprod Med 1996 77% VBA1C

60% VBA2C

0.0% yes, 25% induced n=5 TOL after 2 c/s; n=124 TOL after 1+ c/s too few to make evaluation OBs interviewed underestimated VBA2C success rates greatly;

VBAC after induction was 42% vs. 88% VBAC in spontaneous labor

Bretelle,F et al.  Journal Gyn-OB Biol Rep 1998 65% VBA2C success rate probably 1% true rupture, but data is unclear; 3% scar sprtn  unknown n=96 TOL after 2 c/s yes unknown pitocin use

did not separate scar dehiscences from rupture; only 1 of 3 'dehiscences' is listed as needing surgery so classify this one as a rupture 

Abbassi, H et al.  J Gyn-Ob Biol Rep 1998 50% success rate 1.5% true rupture; 3% scar dehiscence  unknown n=130 yes no case of perinatal death or morbidity from ruptures

scar dehiscences/ruptures mostly due to 'poor obstetrical conditions'

Caughey, AB et al. Am J Ob-Gyn 1999 unknown, this was a rupture study 0.8% rupture-1c/s

3.7% rupture-2c/s

yes, more than 50% had pitocin at some point n=3757 with 1 prior c/s

n=134 with 2 prior c/s

yes for 'motivated' patient with risk counseling found much higher rate of rupture in women with 2 c/s; 4.8x adjusted risk ratio

one of the few studies to adjust for confounding factors like pitocin use

Faridi, A and Rath, W A Geburt. Neon. 1999 not given; review of literature 0% - 2.8% yes many studies yes "maternal and fetal outcomes in women who have had multiple previous sections do not differ from those in women after ordinary cesarean section...these women should be treated no differently than those who have had only one cesarean delivery."
Burke, AE et al. Ob-Gyn 2000 not given, this was a  rupture study not given yes, 56% of ruptures were induced, and 36% of ruptures had PGE2 gel n=25 ruptures over 10 years, plus 25 controls does not give any opinion Study examined whether there were any common factors among the 25 ruptures that occurred over 10 years at their institution; none reached statistical significance, including number of prior cesarean deliveries


VBAC after Multiple Previous C/S Success Rates

Contrary to what many doctors will tell women, most VBA2C studies have found very good success rates in women undergoing a 'trial of labor' after 2 or more previous c-sections.  Success rates, of course, depend on the study, with some VBAC rates as low as 45% and others as high as 90%. That's quite a range of success rates---so why the wide range?  There are a number of factors that influence the VBAC success rate, including the purpose of the study, the protocols of the study, the choice of provider, how much intervention is used, etc.  

Studies designed to help promote VBAC or lower overall cesarean rates will have higher success rates (70-80%) than those that simply reflect the overall rate of VBACs in the general population (success rates in these studies tend to average about 45-65%).  Also, the protocols of the study influence the success rate; studies that use a high rate of inductions have documented that VBAC rates are generally lower when labor is induced.  Furthermore, the choice of provider can influence the rate of VBAC success; nurse-midwives often have higher rates of VBAC success (about 2.8x the national average) and direct-entry midwives probably have even better rates.  Other studies have shown that some OBs have a very low rate of c-sections in general while others have a very high rate indeed; it is logical that OBs with a low c/s rate will probably have a higher VBAC rate overall than OBs who are quick to resort to surgery.

So VBAC success rates will vary widely depending on the purpose of the study, the type of providers in the study, the protocols of the study (including the rate of induction), and the personal cesarean rate/philosophy of the individual providers in the study.  These varying success rates are summarized as following. Only studies in which it was possible to determine success rates specific to VBA2+C were included here.

Note: Be aware that some of these totals may not reflect the numbers given on an abstract or in the first glance at a study, which may only quote the rate for all VBACs instead.  Because of this, some totals had to be derived from data in the full text of studies in order to get success rates for ONLY VBA2+C.  These are the totals reflected below. 

Table II:  VBA2+C Success Rates

Study Name/Year VBA2C rate Number of TOLs Number of VBA2+Cs
Saldana,  1979 58% n=38 22
Porreco,   1983 81% n=21 17
Martin, 1983 63% n=19 12
Wadhawan, 1983 71% n=31 22
Farmakides,  1987 77% n=57 44
Stovall,  1987 84% n=51 43
Phelan 1987 * 73% n=159 116
Pruett,   1988 45% n=55 25
Flamm,   1988 * 76% n=89 68
Veridiano,  1989 84% n=25 21
Phelan,  1989** 69% n=501 346
Novas,   1989 80% n=36 29
Flamm, 1990*** 64% n=156 100
Wessel,   1990 75%  n=16 12
Hansell, 1990 77% n=35 27
Miller, 1994 75% n=1827 1376
Cowan, 1994* 79% n=75 59
Granovsky, 1994 73% n=26 19
Behrens, 1994**** 70% unknown unknown
Chattopadhyay, 1994 90% n=115 103
Asakura, 1995 64% n=302 194
Davies, 1996 60% n=5 3
Abbassi, 1998 50% n=130 65
Bretelle, 1998 65% n=96 62
Caughey, 1999 62% n=134 83

*(overall average for 2 or more c/s)

**It is unclear whether the Phelan 1987 and Phelan 1989 studies have duplicate subjects (like the Flamm 1988 and 1990 studies do).  Because it cannot be determined for sure, they have been assumed to be separate.  If there are duplicates, the totals given below would be thrown off somewhat but not by a great deal.  The averages below should still hold with little variation.

*** (VBA2+C rate for second half of study only; first half reported in Flamm 1988)

***info from abstract, which only specifies a 70% VBA2C success rate after induction with PGE2 gel.  Because the number of TOLs and number of VBACs are unknown at this time, the success rate only was considered in averaging success rates; the data was not figured into the total number of known VBA2+C TOLs.


Since these VBA2+C rates vary from 45% to 90%, it's hard to generalize what individual VBA2+C chances might be, so it is helpful to come up with an average VBA2+C success rate.  There are two ways to derive this number.  The first is to add all the VBAC rates together and average them (giving each study equal weight).  The second is to count up the numbers of actual VBACs and divide it into the numbers of actual trials of labor.  This latter method might be more accurate, given that some studies are extremely large and some extremely small, and their success rates should probably not be weighted equally.

If you weight each study's success rate equally, it averages to a rate of about 71%.  If you go strictly by numbers alone, there were 3999 trials of labor after 2 or more previous cesareans, and 2868 had VBA2+Cs.  This gives an average 72% VBA2+C rate.  So it is safe to say that the average VBAC success rate after 2 or more previous cesareans is about 71-72%.  Whether you use the 71% or 72% number, this is only slightly lower than the generally accepted VBA1C average of ~75% in VBA1C.  In other words, if you choose a trial of labor after 2 or more previous cesareans, you have an almost 3 in 4 chance of having a VBA2+C.   Those are pretty good odds. 

VBA1C Rates Versus VBA2+C Rates

Many providers delight in telling women that their chances for a VBA2C are lower than after 1 previous cesarean; even ACOG states this.  However, this depends on the study.   Porreco (1983) found an 81% VBA2C rate, versus an 85% VBA1C rate.  Phelan 1987 found an 73% VBA2+C rate, vs. a 82% VBA1C rate average. Similarly, Phelan 1989 found a 69% VBA2+C rate vs. a 83% VBA1C rate.  Cowan (1994) found a 77% VBA2C rate (79% 2+C) vs. an 81% VBA1C rate. Caughey (1999) found a 62% VBA2C rate vs. a 75% VBA1C rate.  Miller (1994) found a VBA2+C rate of 75% versus a VBA1C rate of 83% and emphasized the "decreased likelihood of success" in trials of labor after multiple previous cesareans, conveniently ignoring that 75% means that 3 out of 4 had a VBA2C anyhow, and that this is a higher rate of success than many VBA1C trials!  Asakura (1995) found a 64% VBA2+C rate compared with a 77% VBA1C rate, BUT noted that the VBA2+C rate had risen to 74% by the end of the study period, nearly equal that of the VBA1C rate.  

While some studies found a lower VBAC rate after multiple cesareans than after one prior cesarean, other studies actually found an increased rate of VBACs in those with multiple prior cesareans. Saldana (1979) found a pitiful 39% VBA1C success rate, whereas the population with 2 or more cesareans had a 58% VBA2+C rate. Stovall (1987) found a 75% VBA1C rate, whereas the rate was 79.5% for VBA2C and 100% for a small VBA3C group (or an 84% average for VBA2+C).  Novas (1989) found a 71% VBA1C rate, versus an 81% VBA2+C rate average.   Chattopadhyay (1994) found a much higher VBAC rate in the group with 2 cesareans, 90% vs. 54% for VBA1C.  And Flamm (1988) did not find a significantly different VBAC rate among those with 1, 2, or 3 prior cesareans.  

Many women report that doctors consistently underestimate their chances for VBAC after multiple prior cesareans.  Indeed, Davies (1996) found that while the obstetricians interviewed in their study estimated VBA1C rates at their hospital quite accurately, they consistently underestimated VBA2C rates.  Their estimates of VBA2C success ranged from 0-70%, with the average guess at 44%.  In fact, although only a few patients at their hospital tried VBA2C that year, 60% did succeed.  And the above analysis shows that VBA2C success rates actually average about 71-72% overall. The problem is that few doctors know it.  

So VBA2+C rates are not necessarily lower than VBA1C rates; it depends on the study looked at, and probably on the specifics of the factors that typically influence VBAC rates.  

Factors Which Influence The Odds for VBA2+C

There are many factors which influence VBAC success.  OBs have been studying them in order to try and predict 'who would most benefit from a trial of labor'.  However, they have found that while they can often predict women who are MOST likely to have a VBAC, large numbers of women who are NOT predicted to have a VBAC end up having one anyhow, despite their providers' lack of confidence. 

Jakobi (1993) found that 67% of women that were predicted  not to have a VBAC ended up having a VBAC anyhow.  If 2/3 of the women they predicted would 'fail' at VBAC ended up proving them wrong, obviously you should treat any statement that your chances of VBAC success are very low with significant suspicion.  While they can often predict VBAC 'success' with some degree of accuracy, authorities have not found any reliable way to predict VBAC 'failure' and are often wrong.

The following are factors that may influence the odds for VBA2+C.  However, again, keep in mind that while some factors may increase your odds for VBAC, no factor can reliably be used to predict VBAC 'failure'.   The fact is that many women do go on to have a VBA2+C, even when the 'odds' are seemingly against them (Kmom did!)  

Previous Vaginal Birth

Doctors have long noted that women who have had vaginal births as well as cesarean births tend to have higher rates of VBACs.  Several VBA2C studies also noted this (Porreco 1983, Phelan 1989, Hansell 1990, Chattopadhay 1994, Asakura 1995).  However, women who have never had vaginal births also have a good rate of VBACs.  In Phelan 1989, 2/3 of women (67%) who had never given birth vaginally went on to have a VBA2+C, and in Asakura 1995, 66% had a VBA2C. In Chattopadhyay 1994, 83% of those who had never had a previous vaginal birth went on to have a VBA2C.  

Thus, even if you have never had a vaginal birth before, your chances of VBAC are still good. Although a prior vaginal birth or even a prior VBAC is no guarantee of a VBAC, it does significantly increase the odds. Even so, most women with no prior vaginal births do go on to have a VBAC.

VBA2+C Rates By Primary Indication for Cesarean 

Studies have documented that the highest VBAC rates come when the first cesarean(s) occur for non-repeating reasons, like a breech position in the first c/s and then an automatic repeat c/s the next time, or fetal distress in the first c/s plus an automatic repeat c/s, etc.  The VBAC rates in these cases are often >80%.  

VBAC rates do go down somewhat when the reason for the original cesarean was CPD (so-called 'Cephalo-Pelvic Disproportion'), Failure to Progress, 'labor dystocia', 'arrest of labor', etc.  However, even in these cases, the chances are still as good for a VBAC as they are for a repeat c/s after TOL, usually much better.  Nor does prior cesarean for CPD seem to increase the rate of uterine rupture (Phelan 1987, Stovall, 1987, Tahilramaney 1984, Rosen 1991, Leung 1993, Rageth 1999). 

Some doctors insist on pelvimetry (measuring the pelvis manually or by x-ray) after a CPD cesarean in hopes of being able to predict whether a VBAC is likely or not, but studies show this does not reliably predict vaginal birth.  Pelvimetry is a static measurement and does not take into account the changes in the pelvis and the molding of the baby's head that occur during labor and birth, both of which can significantly increase the room there is for baby.  

Many women predicted (via pelvimetry) to have 'inadequate pelvises' and to need future CPD cesareans go on to have VBACs anyhow (Goer, Obstetric Myths vs. Research Realities). For example, Thubisi (1993)  found that 55% of women in the TOL group judged to have an 'inadequate' pelvis by postpartum x-ray pelvimetry had a vaginal birth anyhow.  If more than half the women predicted to have inadequate pelvises birthed vaginally, pelvimetry is not useful and may be harmful.  The authors called x-ray pelvimetry 'not necessary' for TOL, and noted that "it increases the caesarean section rate and is a poor predictor of the outcome of labor."

Other OBs have tried to determine other ways of determining true CPD, including strict interpretations of stalled labor parameters.  O'Herlihy (1998) found that only 84 women out of 42,793 actually met these strict criteria for 'true' CPD when carefully reviewed.  40 of these women with 'strictly defined' CPD had a TOL, and 68% birthed vaginally, 7 with larger babies.  15 of these 40 women had had a c/s at full dilation (10 cm) previously, yet 73% went on to birth vaginally with no serious maternal or neonatal problems.  They concluded that even strict definitions of CPD should not be used as an automatic 'recurrent' indication for ERCS.

In addition, many cases of past 'CPD' are actually caused by baby malposition, which may not recur in subsequent pregnancies and can often be prevented as well (see below).  And many VBAC moms have given birth vaginally to babies even larger than their 'CPD' baby as well.  Since pelvimetry and even strictly defined CPD diagnoses are poor predictors of future birthing modes, most authorities feel that women with prior cesareans for CPD should not be denied a TOL, unless there is gross malformation, previous serious pelvic injury, or extreme malnutrition.  

In women with one previous cesarean for CPD, the VBAC rate ranges widely.  It averages around 66% or so most often  (Goer, ibid), but sometimes goes as high as 80% (Cowan 1994). And many women have had VBACs after 2 previous cesareans for CPD (see Phelan, 1987, below), have had VBACs after previous 'failed' trials of labor, and have had VBACs after dilating completely and pushing both times (Kmom did!).  The following studies specifically examined VBA2+C rates after 1 or more cesareans for previous CPD/FTP.

Table III:  VBA2C Rates After Previous Cesarean for CPD

Study and Year VBA2+C Rates After Previous C/S for "CPD" Comments
Porreco, 1983  78% --
Phelan, 1987 77%  rupture rates not increased in group with prior CPD cesarean
Farmakides, 1987 70% --
Stovall, 1987 77% 37% of CPD VBACs had larger babies than the original 'CPD' baby; ruptures not increased in group with prior CPD cesarean
Phelan, 1989 64% after 1 previous c/s for CPD (and apparent ERCS) second c/s was apparently elective
"        " 53% after 2 previous c/s with full labors (i.e. no ERCS) authors don't really specify adequately.  Apparently, 2nd c/s not elective but 'failed' TOL; there were 2 full labors but both c/s not from CPD (CPD plus fetal distress, etc.)
"        " 56% after 2 previous c/s, both  for CPD/FTP in labor  2nd c/s apparently not elective but a 'failed' TOL; both c/s for CPD in labor, a situation many docs would consider a contraindication to further TOL--yet 56% succeeded
Novas, 1989 93% 20% of CPD VBACs had larger babies than original 'CPD' baby
Hansell, 1990 50% 43% of CPD VBACs had larger babies than original 'CPD' baby
Asakura, 1995 63% --


So although VBAC rates are highest in the face of non-repeating c/s indications (like breech, fetal distress, etc.), VBAC rates after so-called 'repeating indications' like CPD are still generally quite favorable.  Many women even give birth vaginally to babies that were bigger than their original 'CPD' babies (something that should not happen with a real case of CPD), and some women gave birth vaginally even after two previous cesareans for 'CPD' (Kmom did!).  Women who have been told that their pelvises are 'too small' or that they can only have a VBAC if their next baby 'is much smaller' should understand that these diagnoses are dubious at best.


For many years, it was thought that a big baby (macrosomia, usually defined as >4000g or roughly, babies 9 pounds or larger) would tend to distend the uterus too much and thus predispose it to uterine rupture, so a trial of labor was regularly 'prohibited' among women with babies suspected to be big.  One study (Aboulfalah 2000) did find an increased rate of rupture, but apparently did not control for pitocin use, and since many OBs still use induction for suspected macrosomia, this might be a possible cause of the higher rate.  Most studies, on the other hand, have repeatedly not found higher rates of rupture with macrosomic babies (see Flamm in Birth After Cesarean, Tahilramaney 1984, Leung 1993, Rageth 1999).  A big baby probably does not predispose to uterine rupture, and most authors now agree that a trial of labor should not be excluded on this basis.

Because of the past policy of exclusion, there is little data to be found regarding macrosomia and VBA2+C.  Even so, it is probably not reasonable to exclude women with multiple prior cesareans from a TOL when there is suspected fetal macrosomia. In particular, given the tremendous false positive rate in predicting macrosomic babies (predicting macrosomia is only slightly more accurate, on average, as flipping a coin), macrosomia should probably not be a factor in deciding whether women with multiple prior c/s should have a TOL.

VBAC success rates with macrosomic babies do tend to be somewhat lower than with average-sized babies. Most doctors would say that the rate is lower simply because big babies may be 'too big' to fit through the mother's pelvis.  However, the rate of women who have had cesareans for "CPD" and then gone on to VBAC babies even larger than their "CPD" baby (see above) suggests that this view is too simplistic.  Instead, there are probably a number of different factors at work. 

First, it's possible that if larger babies have less 'wiggle room' than smaller babies, it may make birth a little harder to negotiate.  This may be especially true if the baby is in a less-than-optimal position (i.e., a hand by the face, head tilted to one side, or face towards mother's abdomen instead of towards her back), where a larger size may make it more difficult for baby to fit through the pelvis or to readjust its position so it can come out easier.  Many women with primary cesareans for "CPD" find that baby malposition was the problem, and this may have been harder to resolve with a larger baby.  Many of these women find that by preventing malposition from recurring (see FAQ on Baby Malposition), they can go on to have a VBAC. 

Second, physician bias and protocols for macrosomic babies may also account for lower VBAC rates.  Research clearly shows that if doctors even suspect a larger baby, labor is managed differently and a higher c/s rate results, whether the babies are actually bigger or just average-sized (Leaphart 1997; other references in Macrosomia and Induction FAQ).  Doctors may create self-fulfilling prophecies with large babies by expecting problems, and may create higher c/s rates by regularly employing more induction and other intervention with larger babies.  The VBAC rates for macrosomic babies may not have to be lower, but may instead simply reflect the biases and overly interventive protocols used by most doctors with cases of suspected macrosomia. 

Third, a common tactic when macrosomia is suspected is to induce labor early in hopes of reducing the chances of a cesarean and avoiding the shoulders getting stuck (shoulder dystocia).  Yet non-VBAC studies show inducing early for macrosomia often actually increases the rate of cesareans (sometimes to more than 50%). VBAC studies also show that induction for macrosomia increases the c/s rate, decreasing the VBAC rate strongly. In Rageth 1999, the VBAC rate dropped from 74% down to 57% if mothers were induced for macrosomia. Although the sample size was extremely small, Leaphart 1997 found that induction for macrosomia dropped the VBAC success rate from 71% down to 29%. Other data seems to confirm that induction in general tends to lower VBAC success rates (Davies 1996, among others), and may increase the risk of rupture (Zelop 1999, Rageth 1999, Ravasia 2000). Furthermore, in some non-VBAC studies, induction was even associated with a higher rate of shoulder dystocia, yet another  reason to avoid it (see Macrosomia and Induction FAQ for references).  

However, even with all of these possible limitations, VBAC still occurs the majority of the time when macrosomia is present. None of the VBA2C studies analyzed for this FAQ examined macrosomia as a variable for VBAC success, but in VBA1C studies, VBAC success rates with macrosomic babies ranged from 55% (Holt 1997, Flamm 1989) to 64% (Davies 1996, Aboulfalah 2000) to 70% (Abbassi, second 1998 study).  Some of these were undoubtedly induced, so it's possible that by having women labor spontaneously instead, the VBAC rates with macrosomic babies might be even better.

With success rates at least 55%-70% and probably no increased rate of uterine rupture, a TOL with a macrosomic baby is a reasonable option.  Choosing a midwife that is comfortable with 'big babies', knows how to prevent or minimize potential risks like shoulder dystocia, and does not generally use induction for macrosomia may help increase the chances for a favorable outcome.

Baby Malposition

As noted above, many women with past cesareans for "CPD" or "FTP" have actually found that the problem really was baby malposition, a factor many doctors tend to ignore.  As long as the baby is head-down, most doctors (and even many midwives) pay little attention to fetal position.  However, if baby is facing the mother's tummy instead of her back (posterior instead of anterior), has its head tilted to one side (asynclitic), or has a hand/arm by its head (compound presentation or 'nuchal' hand/arm), labor problems often occur and baby can get 'stuck'.   Although some of these babies resolve their positions and are born vaginally, a high percentage of them end up with a c/s.  Some posterior babies can be born vaginally (usually those that are small and have their chins well-tucked), but many also end up with a cesarean.  In addition, labors with malpositions are often  long, hard, very painful, and especially difficult, making many of these mothers afraid to face a trial of labor again.

Because baby malpositions tend to place uneven pressure on the cervix, dilation often stalls, and the labor is labeled "Failure to Progress" (FTP).  Even if dilation finishes, the baby's less-than-optimal position often causes it to get 'stuck' (deep transverse arrest, or arrest of descent) and baby often doesn't descend into the pelvis much, so this is usually chalked up to a "too big baby" or a "too small pelvis" (CPD).   Not all cesareans for FTP, CPD, or 'labor dystocia' are caused by baby malposition, but many are.  And many women have gone on to VBAC by learning how to prevent malposition from recurring  (see the FAQ on Malpositions for specifics).  

The modern medical literature largely ignores the problem of baby malposition these days; most information is found in midwifery, doula, or nursing journals, in obstetric journals from non-English speaking countries (especially China), or in chiropractic journals.  Because of this, most OBs either are not exposed to the literature on malposition (and how to resolve it), or consider it much too 'alternative'.  Therefore, there is little mainstream obstetric data on malpositions and VBACs.  

One of the only studies that examines the question is the Rageth 1999 study from Switzerland.  It found that Fetal Malpresentation (either breech or posterior) was significantly correlated with VBAC 'failure', presenting nearly 4x the risk for a 'failed' TOL.  Only 42% of women with fetal malpresentation ended up with a VBAC in their study.  The picture improves somewhat if breeches are removed from the picture; 58% of those with posterior babies in the study did end up having a VBAC (compared to 74% VBA1C rates overall).  The study unfortunately did not specify how many of these babies resolved or did not resolve their posterior positions during the VBAC; this would be information that would be very helpful to know.  Some posterior babies are born vaginally, but most rotate to anterior and thus are able to be born vaginally.  Of those that start anterior and then rotate to posterior, many are born vaginally, though it is not an easy labor.  A very high percentage of those that remain posterior from the beginning to the end of labor ('persistent posterior') end up being born by cesarean.  So it would be interesting to know how many of the 58% of 'posterior' babies having a VBAC in the study had actually rotated prior to birth, how many actually emerged posterior, and how many were posterior from beginning to end.

If you think you may have had a cesarean due to a malposition problem, you should read Optimal Foetal Positioning by Jean Sutton and Pauline Scott, or The Labor Progress Handbook by Penny Simkin and Ruth Ancheta.  These are available from,, or Also be sure to read the FAQ on Malposition on this website for more details, documentation, and references.  Baby malposition CAN affect labor and cause cesareans or 'failed' TOLs, but they do not have to.  There are steps that can be taken to prevent malpositions, or to fix them if they do occur.  (Kmom's stories are a good example of the influence of malpositions!  See below.)

VBA2+C Success Rates and Pitocin Use

Routine use of artificial oxytocin (trade name, pitocin) also tends to decrease chances at VBAC.  Augmentation (adding pitocin after labor has already started spontaneously) tends to impact VBAC rates less than induction (starting the labor from scratch with pitocin or other induction agents), though not always.  Although not all studies have found pitocin use to lower VBAC rates, and although pitocin can be valuable in selected cases when used cautiously and judiciously, many studies have found lower VBAC rates (and sometimes higher dehiscence and rupture rates, see below) when pitocin is used.  

Lower VBAC rates with pitocin use is true for both VBA1C and VBA2+C.  For example, Davies (1996) found that among VBA1C patients, those who were induced had a 42% VBAC rate, whereas those who were not induced had an 88% VBAC rate.  They concluded that "induction of labor in patients attempting vaginal birth after cesarean should be performed only when absolutely medically indicated.  In those patients without a strong medical indication for induction of labor, awaiting the spontaneous onset of labor is recommended."

Looking at only VBA2+C studies, the association between pitocin use and lower VBAC rates also seems to generally hold: 

Table IV:  Influence of Pitocin on VBA2+C Success Rates

Study/Year VBA2+C, No Pitocin VBA2+C with Pitocin Comments
Stovall, 1987 85% 74% mix of both VBA1C and VBA2C in data
Phelan, 1987 91% 70% dehiscence rate was increased in pitocin group but did not reach statistical significance 
Pruett, 1988 64% 30% all dehiscences were found in pitocin group
Flamm, 1988 78% 64% --
Phelan, 1989 83% 58% 2.1% dehiscence in pitocin group vs. 1.4% dehisc. in no pitocin group; pitocin had 1.5x risk for dehisc.


Although not all VBA2+C studies showed a negative effect from oxytocin use (i.e. Granovsky-Grisaru 1994, Chattopadhyay 1994), many studies do (including plenty of VBA1C studies).  Enough studies have documented lower VBAC rates when pitocin is used that the possible advantages and disadvantages should be considered most carefully before a decision is made.  In some cases, careful use of pitocin might help achieve a VBAC, but its routine or aggressive use should probably be avoided.  (See discussion below on pitocin and rupture risks.)

Emotional Homework

Although little scientific data is available on it, many providers and VBAC moms find that emotional processing is an important part of VBAC preparation and may help increase VBAC success.  Although some cesareans are due to purely physical circumstances or mismanagement, many women find that there is an emotional component that may have contributed to their cesareans.  Lack of body trust, a past background of abuse, an over-reliance on or reluctance to question medical authorities, a feeling of helplessness or over-passivity, a prior loss of a baby (due to circumstances like miscarriage, stillbirth, abortion, adoption, etc.), control issues, exaggerated fears of pain in labor, past history of difficult birth in the family, etc. are all factors that can affect a woman's ability to birth freely and without excessive anxiety or intervention. This is such an important issue that an entire section is devoted to it below (see  "Emotional Factors in Considering a VBAC"), and resources for further information are given.

Contrary to what many doctors believe, birth is not a purely mechanical process.  Emotions can and do influence the process of birth, and doing 'emotional homework' before labor can help the process along.  Many women who have had prior cesareans or even one 'failed' TOL found that they had unresolved or deeply troubling issues that weighed on them and may have contributed to the c/s.  Many have found that delving deeply into their emotional 'homework' before the next labor helped them towards a more satisfying birth, however it unfolded.  It is Kmom's opinion that 'emotional homework' is one of the MOST important things you can do to prepare for a better birth.

Professional Labor Support

Many women find professional labor support (in addition to labor coaching from their partners/husbands) to be invaluable.  These are women who are professionally trained to provide extra labor support, in whatever way you need.  These women, usually called 'doulas', receive professional training, generally work for between $200-$500 (depending on your area), and can be found through organizations such as DONA (Doulas of North America,, Birth Works ( ), or  ALACE (Association of Labor Assistants and Childbirth Educators,  If you cannot afford a doula, many are willing to barter or negotiate for their services, or you can ask for a doula-in-training, as they must attend a certain number of births in order to certify and may be willing to come to your birth for free or for a greatly reduced fee.

Some of the many things that doulas do include (adapted from a doula brochure from Cutting Edge Press, 

Sometimes parents are reluctant to hire a doula because they are afraid she will usurp the husband's place in birth, make him feel less needed, detract from the intimacy of the moment, 'take over' the birth, or generally take away from the birth experience.  This is an understandable concern.  However, doulas are there to support both the father and the mother; childbirth is an emotional and physical rollercoaster for both parents, and many fathers are overwhelmed by the experience, especially if the birth becomes challenging at all.  A doula can provide a welcome additional source of support.

Many fathers who were unsure about hiring a doula later reported that their help was invaluable, that it did not detract from the experience at all but rather greatly enhanced it.  They appreciated the experience and 'labor tricks' that the doula brought to the birth, the ability to take an occasional break from labor to eat or go to the bathroom (without having to leave their wife alone or with strangers), the ability to be there emotionally for the mom but without the pressure of being mom's only support, and relief from the pressure of having to know everything about birth in order to keep all the interventions away.  Although many fathers fear that a doula would take away from their place in birth, fathers who have experienced a doula's help almost universally endorse it (Kmom's husband greatly appreciated it!).  

Although little information is available on doulas and VBACs, a meta-analysis of studies on doula use shows that their support can help cut the c-section rate by almost 50%!  Women who utilize doulas tend to have 25% shorter labors, less intervention (40% less pitocin!), and to need less medication (60% fewer requests for epidurals).  They also tend to have more success at breastfeeding, and feel more emotionally satisfied with their births.  (See the FAQ on Finding A Size-Friendly Provider for references.) Any woman who is considering a trial of labor should probably strongly consider hiring a doula if possible. 

Choose Providers Wisely

Another extremely important way to increase your VBA2+C chances is to choose a truly VBAC-friendly provider.  Many providers pay lip service to VBACs but do not truly support it, impose so many limitations that your chances are greatly reduced, or undermine it in subtle ways without realizing it.  You need to find out YOUR provider's c/s rate and VBAC success rate.  If your provider does not have a low c/s rate, does not have a high VBAC rate, or does  not have much experience with VBACs, you might want to consider another provider.

You should also consider what kind of procedures, routine protocols, and limitations on labors that your provider may insist on. These will tell you more about your chances for VBAC than any study. If your provider is not strongly supportive about a trial of labor for you, seems very fearful of or dwells a great deal upon uterine rupture, then perhaps you need a provider that is less fearful and knows that research supports TOL vs. ERCS.  Also, if the provider places lots of limitations on VBAC labors (must come in in early labor, must dilate a cm/hour even in early labor, mandatory continuous fetal monitoring, mandatory induction before or at term, etc.), you might want to consider finding a more VBAC-friendly provider to increase your chances for a VBAC.  

Certified Nurse-Midwives (CNMs) tend to have about 3x the rate of VBACs as OBs do, and Direct-Entry Midwives (DEMs such as Certified Professional Midwives, Licensed Midwives, etc.) probably have even better VBAC rates.  Because midwives tend to be more liberal in 'permitting' a trial of labor to a wider variety of women than many doctors, and because they tend to be much less interventive in labor and birth, your chances for a VBAC tend to be better with a midwife on the whole.  However, there are VBAC-friendly OBs, and there are 'medwives' that don't truly support VBAC or who are highly interventive.  A certain job title is not enough to guarantee that a provider is truly VBAC-friendly.  Important questions must be asked, with careful attention to the spoken and unspoken messages and beliefs of the provider.  

You should find out  each provider's overall c/s rate (including first-time c/s rate vs. repeat c/s), TOL rate (how many of patients with previous c/s have a TOL), VBAC rate (of those who have a TOL, how many go on to have a VBAC?), and how much experience the provider has with VBACs.  You will also want to know what routine protocols the provider uses for VBACs (see above).  Further guidelines and questions to ask prospective providers about VBAC can be found in VBAC books such as The VBAC Companion by Diana Korte, or Natural Childbirth After Cesarean by Crawford and Walters.

It is also often quite revealing to ask very open-ended questions about important issues such as when and how the provider uses induction, augmentation, monitoring, etc.  Providers often unconsciously tell women what they want to hear at the first interview, but seem to get more restrictive and nervous as the end of pregnancy approaches.  Many VBAC mothers have found what seemed like a VBAC-friendly provider, only to find many conditions, restrictions, and caveats placed on them near term ('you can only have a TOL if the baby is small', 'you can't go past due', 'the baby hasn't engaged yet, you'll need a repeat c/s', 'your cervix is not ripe yet, you'll never go into labor', etc.---NONE of which is supported by research as being important).  So many VBAC moms have experienced these seeming 'bait and switch' tactics (which may or may not be unconscious) that it is vitally important to get all of these issues clarified ahead of time.  

And remember, it is almost never too late to switch providers if you begin to have significant reservations about whether your provider really is the right one for your VBAC.  Providers really have quite a wide range of policies and attitudes about VBAC, even in the face of significant complications.  Although you may find the perfect person to support you in your VBAC, many VBAC moms have found that they have had to switch their care partway through a pregnancy, sometimes even very close to term.  A few women have even switched providers in the middle of labor! You owe it to your provider to listen carefully to their reasoning and consider their opinions; they owe it to you to provide you with research to back up their opinions, and time to discuss the issues adequately.  At that point, it is up to you to make a sensible and reasonable decision.  This might be repeat cesarean, going ahead with a TOL under certain guidelines, or switching to a new provider for a TOL without these restrictions.  Remember, YOU are the consumer, and YOU make the final decisions.   


Considering Uterine Rupture Risk

Is the risk of uterine rupture higher when a mother has had multiple previous cesareans?  This question is difficult to answer at this point because evidence is contradictory.  Preliminary evidence from the 80s and early 90s suggested that the risk of rupture was NOT greater for moms with 2 previous cesareans.  However, several studies published in the mid-to-late 90s found that while the risk was still small, there was some increased risk for rupture in women with at least 2 prior cesareans, and that the risk may go up as the number of prior cesareans increases.   

Previously, the American College of Obstetricians and Gynecologists (ACOG) supported a trial of labor in those women with 2 or more previous cesareans who wanted one.  Their latest revised recommendations still supports a trial of labor in these women but does not endorse it as strongly either.  And some doctors, always skittish about women with multiple previous cesareans, are now refusing to even consider a VBA2C.  However, at this time, most providers will still consider a VBA2C, but not all will be truly supportive or may place unreasonable restrictions on it.  Midwives are probably more likely to support a trial of labor after 2 (or more) cesareans, but some OBs and family doctors can still be found that will also offer a fair 'trial of labor' in this situation.

Despite the more recent studies that may show a somewhat increased risk of rupture with multiple cesareans, it's important to note that nearly every single study on VBA2+C--even the most recent---supports a trial of labor for 'motivated' women with more than one previous cesarean.  Even the study that found the highest rupture rates (Caughey 1999) still supports a trial of labor (with informed consent) for those who wish one.  

Cautions About Interpreting the Studies

So what exactly are the rates of rupture in women with multiple previous cesareans?  This is a very  difficult question to discern; there are no easy answers.  The rates of true rupture found in the medical literature varies from 0.0% to nearly 4%.  Most studies found no increase in rupture in those with multiple cesareans, while other studies found 2-5x the rate of ruptures.  However, keep in mind that even in the studies that found (gasp!) "a higher risk of rupture", the overall rate was still low, comparable or just slightly increased over rates of other unpredictable birth complications (see below).  

For example, Leung et al (1993) found that the rate of rupture was about 2% for women with 2 or more c/s, a risk 2.6x that of women with only 1 c/s.  After adjusting for various possible confounding factors, their analysis showed a 3.8x risk for uterine rupture in women with 2 or more c/s!  Yet they also cautioned readers to keep those numbers in perspective, since 98% of women with 2 or more c/s in the study labored and birthed safely.  Again, it is important to look at the whole picture when considering these numbers.  

In general there is a great deal of difficulty in analyzing uterine rupture studies because so many factors and definitions have to be considered.  True uterine ruptures are different than benign scar dehiscences, yet some studies do not separate out these and consider them together, resulting in very high-appearing 'rupture' rates.  Yet benign dehiscences have very little impact on labor and birth, are often discovered only accidentally, and rarely affect the health of either the mother or baby.  Most careful researchers make a definite distinction between true ruptures and benign dehiscences.  In the 90s, more and more researchers began considering only true ruptures when evaluating risks, since dehiscences seem to have little clinical relevance.  But because not all researchers draw careful distinctions like these, uterine rupture research can be misleading.

When you read abstracts listing dehiscence and/or rupture rates, it is important to know which they are referring to, and if possible to get the study so that you can confirm the numbers.  For example, Phelan 1989 says in its abstract that the overall rate of uterine dehiscence was 3%.   Some people would read this as a rupture rate of 3%, but actually the rupture rate in the study was 0.0%---there weren't any true ruptures in the study.   Even if you do want to consider dehiscence rates (and as noted, many don't anymore), the overall dehiscence rate in this study was 3%, BUT the rate in the TOL group was 1.8% vs. 4.6% in the ERCS group.  So if you read the abstract without full understanding or did not read the entire study, you might assume that this study had a rupture and/or dehiscence rate of 3%, when actually the dehiscence rate for the TOL group was 1.8% and the rupture rate was 0.0%.  That makes a LOT of difference!

Another factor to consider is the protocols that  women labor with in a trial of labor.  For example, excessive use of oxytocin (synthetic version: pitocin or pit.) is known to be a risk factor for uterine rupture, and several studies have connected it with many of the cases of uterine rupture out there.  Yet not all studies specify whether pitocin was routinely used in their trials of labor, what the dosage was, when it was started, how often the dosage was increased, etc.  Although some studies have found no increased risk with pitocin, other studies HAVE found an increased risk, particularly for induction.  

A number of cases of uterine rupture may have been preventable or the damage to babies more minimized.  Ruptures have been found in women who have had their labors induced or augmented with multiple labor drugs or high levels of pitocin, had epidurals (which may decrease the mother's ability to feel the abnormal pain of rupture), and/or were inadequately monitored because of staffing concerns or carelessness (often even after the mother complained that 'something was wrong').  Some recent studies have tied many cases of rupture to induction (especially use of multiple induction agents or induction with an unripe cervix), excessive use of pitocin, pitocin starting in the latent stage of labor, poor management of labor, or 'poor obstetric conditions'.  So although a certain percentage of ruptures may have occurred in a study, it doesn't follow that the same amount would occur in other populations automatically.  Some cases may be preventable.  

Labor protocols may also increase a patient's risk of rupture.  Because many doctors require that their VBAC patients have their labors induced early, that they have pitocin augmentation unless they dilate 1-1.5 cm per hour, have an epidural placed early in labor ("just in case"), or face other highly interventive protocols, the risk of rupture may be increased among these patients.  To compare these patients' risks of rupture to the risk faced by women laboring spontaneously and without interference or augmentation is unfair and 'stacked', yet most studies do so regularly.   Keep in mind that almost NO studies of any real size have researched the uterine rupture rate among women in spontaneous labor, with no pitocin or other drugs, etc.  We don't know what the 'true' underlying rate of rupture may really be. 

Also, rupture rates seem to have gone up over time (Farmer 1991, Leung 1993, and others), which seems to indicate the influence of other factors. In particular, the VBAC studies done in the 90s seem to have slightly higher rates of rupture overall compared to those done in the 80s, if considering only the rate of true rupture.  This may be because in the 80s when VBAC was a relatively 'new' concept, the candidates were selected more carefully and monitored more carefully, or because the rates of induction and augmentation with strong drugs vastly increased in the 90s (including in VBACs), or that the number of trials were small in the 80s and it took the larger trials in the 90s to reflect increased rupture rates, or a combination of all three factors. Thus it is very difficult to accurately compare rupture outcomes among various studies, and rates seem to vary widely.  However, even with these limitations, some comparison can be useful.  

VBA2C Studies and Rupture Rates

Among the VBA2C studies cited analyzed for this FAQ, the uterine rupture rate varied from 0.0% to 3.7%.  Rupture rates for trials of labor after 1 c/s vary greatly too, but generally run < or = 1%.  Of the VBA2C studies below, a number seem to have rates from 1-2%, although some are below 1% as well, and quite a few found NO ruptures at all.  Here are the VBA2+C studies that had rupture rate information specified in them.

Table V:  VBA2+C Rupture Rates (Low Transverse Scars)

Study/Year Number TOLs True Ruptures Pitocin Used? VBA2+C Rate Comments
Saldana 1979 n=38 0/38 = 0.0% rarely 22/38 = 58% VBA2+C --
Porreco 1983 n=21 0/21 = 0.0% yes, 1/3 had oxytocin 17/21 = 81% VBA2+C  --
Martin, 1983 n=19 0/19 = 0.0% yes 12/19 = 63% VBA2+C no dehiscences or ruptures in TOL group; one occurred in ERCS group, however
Phelan, 1987 n=159 0/159 = 0.0%

(5 ruptures in study, but all in classical or fundal scars. No ruptures in the low transverse scar group. 

 yes, nearly 50% received pitocin, mostly for augmentation 116/159 = 73% VBA2+C The rate of dehiscence was the same in TOL and ERCS (1.9%)

rate of dehiscences "was unrelated to...the number of prior cesarean births."

Farmakides, 1987 n=57 0/57 = 0.0% yes, in 5 women 44/57 = 77% VBA2+C 0 ruptures, 1/57 dehiscences (rate of 1.8%)
Stovall, 1987 n=51 0/51 in multiple c/s group (0.0%) yes 43/51 = 80% VBA2C no ruptures in multiple c/s group, but 1 rupture in the 1 prior c/s group
Pruett, 1988 n=55 0/55 ruptures = 0.0% yes, all dehiscences were in pitocin group 25/55 = 45% VBA2+C no complete ruptures; 5.5% dehiscences, all in pitocin use group.  There were no ruptures OR dehiscences in the group that didn't get pitocin
Flamm, 1988 n=89 0/89 = 0.0% yes 68/89 = 76% VBA2+C part of a larger VBAC study
Phelan, 1989 n=501 0/501 = 0.0% yes, more than half got pitocin 346/501 = 69% VBA2+C 0 ruptures in the TOL group; 1.8% dehiscences

The dehiscence rate was 1.4% without pitocin, and 2.1% with pitocin (pitocin has 1.5x risk for dehiscences)

Novas, 1989 n=36 0.0% rupture in low transverse c/s scars (0/35?) yes, about half induced 29/36 = 80% VBA2+C 0 ruptures in multiple low transverse scars; 1 rupture in woman with 2 classical scars receiving pitocin augmentation
Hansell, 1990 n=35 0/35 = 0.0% rupture in TOL group no 27/35 = 77% VBA2+C no ruptures in TOL group; 1 rupture in ERCS group
Leung, 1993 n=1165 23/1165 = 2% yes, ruptures increased in group with 'excessive amount of oxytocin' not specified rupture rate in VBA1C TOL was 0.82%; rupture rate in VBA2+C TOL was 2% (rupture risk 2.6x, adjusted risk 3.8x)

74% of ruptures occurred when pitocin used very aggressively in early labor; see discussion below

Granovosky, 1994 n=26 0/26 = 0.0% ruptures yes, 54% had pit. 19/26 = 73% VBA2+C Israeli study
Cowan, 1994 n=75 1/75 = 1.3% ruptures after 2+C yes, 39% had pit; 3/5 ruptures had pitocin 59/75 = 79% VBA2+C 1 rupture/72 TOL in 2 c/s group; woman had 'unknown' scar. (1.4% rupture in 2 c/s group, 0% in 3 VBA3C moms; avg. 1.3% 2+ c/s)
Chattopadhyay, 1994 n=115 0/115 ruptures = 0.0% ruptures some 103/115 = 90% VBA2C no ruptures, one dehiscence for 0.8% dehiscence rate overall
Miller, 1994 n=1827 32/1827 ruptures= 1.7% average VBA2+C ruptures vs. 0.6%  VBA1C ruptures; about 3x risk on average yes 1376/1827 = 75% VBA2+C 29 ruptures in 2 c/s (1.8% rate) and 3 ruptures in 3 c/s (1.2% rate); not controlled for pitocin use
Asakura, 1995 n=302 3/302 = 1% true rupture rate yes, 'liberally' 194/302 = 64% VBA2+C 6/302 = 2% dehiscences; 3 ruptures (1% rate).

Found that multiple c/s did NOT increase risk

Davies, 1996 n=5 0/5 ruptures = 0.0% ruptures yes, 25% induced 3/5 - 60% VBA2C  very small VBA2C group
Abbassi, 1998 n=130 2/130 = 1.5% rupture rate (noted to be from "poor obstetric conditions") ?; unknown but probably 65/130 = 50% VBA2C rate Both ruptures from 'poor obstetric conditions', see references for commentary
Bretelle, 1998 n=96 1/96 = 1% rupture? ?; unknown 62/96 = 65% VBA2C 3 dehiscences listed, apparently one was a rupture? unclear status on this
Caughey, 1999 n=134 5/134 = 3.7% rupture rate in multiple c/s group yes, more than 50% had pit, but was controlled for 83/134 = 62% VBA2C Rupture rate after 1 c/s was 0.8% vs. 3.7% after 2 prior c/s; after adjusting for confounding factors, 2 prior c/s had 4.8x risk. 

* Note that the number of trials of labor in this table on VBA2C ruptures is different than the number of trials of labor in the table on VBA2C success rates.  This is because some studies specified only VBAC rates but had no information on number of ruptures or rupture rates, or vice versa.  Only studies in which specific numbers were available for each of these categories were included in the tables on those subjects.  This is why the number of trials of labor seem different on the surface.


If you add up all the data, there were 67 ruptures in 4,935 trials of labor.  That translates to a 1.4% rate of true rupture in VBA2+C trials of labor.  True rupture rates in VBA1C TOLs vary from study to study but generally average between 0.4% and 1%, so this does represent a somewhat increased risk rate (although please note that the risk of other emergency complications in labor is around the same or more--see discussion below).  With informed consent and an eye to reducing risks (and keeping in mind the very real risks of repeat cesarean sections and benefits of vaginal birth), women and their providers can still logically and reasonably choose a trial of labor after multiple prior cesareans.  And in fact, nearly every study also concludes that this is a reasonable choice.

It is VERY important to note that a number of the ruptures come from 'poor obstetric conditions' (Abbassi 1998, Asakura 1995), questionable aggressive management policies for VBAC or excessive pitocin use (Leung 1993).  While some studies examined the role of pitocin use, other large series did not (Miller 1994, which did have a higher rate of ruptures after multiple cesareans).  A number of the ruptures in the above studies were probably caused by injudicious management, plus at least a few ruptures were in women with 'unknown' scars (which might have been classical scars).  Keep in mind, therefore, that the 1.4% rupture rate may be artificially high.  

Although it is difficult to say for sure, it is quite likely that aggressive management and/or injudicious use of pitocin added to the number of ruptures, and that by avoiding these policies,  it is quite likely that the rupture rate in VBA2+C could be lowered.  However, what the 'true' rate of naturally-occurring rupture would be in VBA2+C is unknown.  It may or may not still be increased over VBA1C rupture rates.

Discussion of Specific Rupture Studies

Discussion of specific VBA2+C rupture studies is going to, of necessity, concentrate on the studies that did involve uterine rupture, which may give a mistaken impression that uterine rupture occurs more often than it really does.  So it's important to begin by emphasizing that the majority of VBA2+C studies found NO ruptures at all.  Many of these were small studies, it's true, but some were larger and would be expected to have at least some ruptures (and together add up to plenty of trials of labor which collectively should show some ruptures too).  That 13 studies found NO ruptures at all is quite encouraging.  The following studies found a 0.0% rate of true uterine rupture in their VBA2+C patients with known low transverse or low vertical scars:

On the other hand, other studies have found some uterine ruptures in women with 2+ prior cesareans, as is inevitable.  That many of these studies fall in the mid-to-later 90s is an interesting coincidence. As noted above, perhaps the difference is simply that women who had a trial of labor were selected less judiciously as people became more relaxed about a TOL, that more pitocin or other drugs were used (and more aggressively, especially for induction or augmentation of early labor), or simply that a greater amount of subjects were used (which would have more power to detect overall rupture rates).  It will be interesting to see what rupture rates do in the future, although with the current very high rate of 'active management' techniques they may not go down at all.  

The following are VBA2+C studies in which uterine ruptures occurred and there is relevant information about these ruptures for discussion.  Further summaries of the studies can be found in the reference section.

Flamm 1988 was a multicenter study of VBAC TOLs in women with 1 (n=1687), 2 (n=82), or 3 (n=7) prior cesareans.  There were 3 true ruptures in the whole study, all occurring in women with one prior cesarean. 2 of the 3 ruptures occurred in women receiving pitocin augmentation in early labor (much like Leung 1993, see below).  There were no ruptures in the group with multiple previous cesareans.   

Flamm 1990 was a continuation of this same multicenter study, with data from 3 more years added on for a total of 5733 trials of labor over 5 years.  The overall rupture rate for the whole study was 0.2%.  About 29% of the TOL group received pitocin in their labors; the VBAC rate was 68% in the pitocin group versus 78% in the group without pitocin.  There were 10 cases of uterine rupture overall, 6 of which involved the use of pitocin (60%).  The rate of rupture in pitocin labors was 0.4% versus 0.1% in labors not using pitocin, although the difference did not reach statistical significance. 

In the Flamm 1990 study, 245 total patients had a TOL after 2 previous cesareans (89 of whom were apparently accounted for in the 1988 study).  Although there were no ruptures in the 1988 study in the multiple c/s group, there was at least one listed in this study (although the patient apparently had had 2 prior classical cesareans, which rupture more often, and had labored at home apparently without monitoring).  Although the authors don't specify the rupture rate in the multiple cesarean group, the authors do note that "the incidence of uterine rupture in this group did not differ significantly from that in the group of patients with one previous cesarean."  

Therefore it seems logical that this one rupture (after 2 apparently classical cesareans) was the only rupture in the 2+ c/s group, which probably means that there were no ruptures in the group with multiple low-transverse cesareans.  However, since this is all based in interpolation or 'guessing between the lines', the rupture rate for 2+ c/s is not included in the table above.  The important point from this study is simply that the rate of uterine rupture was NOT increased in the multiple cesarean group.

Phelan 1989 studied 501 women who had a trial of labor after 2 prior cesareans.  They found 0.0% true ruptures in the TOL group vs. a 0.2% rate in the group with elective repeat cesareans. They found a 1.8% dehiscence rate in the TOL group vs. a 4.6% dehiscence rate in the ERCS group.  57% of patients received some pitocin in labor, although the vast majority of this (94%) was from augmentation.  In those who received pitocin, they found that the dehiscence rate was significantly increased (2.1% vs. 1.4% in the group not receiving pitocin).  This translated into a 1.5x risk for dehiscence when pitocin was used.  Although this did not apparently impact ruptures, the trend towards increased risk for dehiscence with pitocin is notable.  

Leung 1993 came from the opposite pole and started with uterine ruptures, looking to see if any factors were more common in women with ruptures.  They studied 70 cases of uterine rupture out of 8513 trials of labor over a 7-year period (0.8% rupture rate). They found that the risk of uterine rupture was increased in those receiving an 'excessive amount' of pitocin (2.4x risk), those who experienced 'dysfunctional labor' (8.1x risk), and those who had a history of two or more cesareans (3.8x risk).  On the other hand, they found that macrosomia, epidurals, history of VBAC, unknown uterine scar, and history of c/s due to "CPD" were not associated with rupture.

Interestingly, the authors noted that the incidence of uterine rupture increased significantly over the years of the study (1983-1990).  They provided no further details, but it would have been interesting to know if the rate of pitocin use in VBACs had increased during that time.  This echoes the observation that the uterine rupture rate seems to have increased somewhat over time, although why is a matter of speculation at this point

The most interesting thing about the study was the amount of pitocin used and especially when and how pitocin was used77% of women who ruptured had received pitocin during the labor, a very high rate.  But most importantly, 2/3 of the women who ruptured had received pitocin in the early (or latent) stage of labor.  This raises the question whether aggressive 'augmentation' of early (latent) labor is really appropriate in VBAC moms.  

In the study, women without prior cesareans who had contractions but were in early labor could be sent home, whereas women with prior cesareans who had had contractions but were in early labor were not permitted to go home. In fact, 76% of women who eventually ruptured were admitted at < or = 3 cm dilation, which is considered LATENT or EARLY labor, and if they were not VBAC moms, it would be controversial whether they should have been admitted at that point.  Early labor is often periodic before it picks up into 'true' labor, and many women also experience 'prodromal' labor (so-called false labor, which may come and go for days before active labor kicks in).  Keeping the VBAC moms and then augmenting that early or false labor so aggressively with pitocin may have created an increased opportunity for rupture.  

Once they were admitted, protocols called for an automatic IV line.  If the cervix did not dilate significantly within 2 hours, the patient was supposed to receive morphine sulfate for 'sedation'.  If there were some contractions but little or no change in the cervix after 4 more hours, pitocin was started, with doses increasing every 30 minutes.  It didn't matter if the cervix was unripe and dilation almost nil; pitocin was used.  The authors note defensively that their residents were "constantly caring for a large number of patients and could not await labor progress" and so initiated pitocin without delay and before the occurrence of 'dysfunctional labor' in a large number of patients. 

In fact, 69% of those who ruptured received pitocin at < or = 3 cm dilation.   This is a very telling point (one derived from the data in the study, for the authors do not point it out).  One of the risks of pitocin is uterine rupture, especially when used with a cervix that is unripe.  So what did the protocols call for?  Aggressive pitocin 'augmentation', even on cervices that were < 3 cm dilated.  Yet considering only the ruptures that occurred WITH pitocin, 89% occurred when pitocin was started at < or = 3 cm dilated (another derived data point).  So is it really fair to blame rupture on 'dysfunctional labor' or is it instead due to aggressive augmentation in the latent phase of labor, which in non-VBAC patients is often allowed to come and go until it settles into a steady pattern on its own?  

The authors discuss the dangers of 'arrest disorders' and 'dysfunctional labor' ( 8.1x the risk for rupture), and advocate that if labor arrests and 'judicious' pitocin augmentation fails to resolve the arrest disorder, the trial of labor be terminated by cesarean.  The conclusion to their study is that patients with history of c/s "be observed closely for progression of labor" and that arrest disorders that persist despite pitocin require a cesarean.  

This is the reason that many doctors require that you dilate 1-1.5 cm per hour in a TOL; they are afraid that if you do not dilate quickly that you are predisposed to uterine rupture.  Their answer is to add pitocin in order to avoid rupture, a contradictory statement if ever there was one!  Similarly, it is ironic that they probably kept VBAC moms in the hospital in the latent phase of labor in order to protect them (because of their fear that an unmonitored uterine rupture might occur out-of-hospital), yet because of their policy of aggressive augmentation even in early labor, they may have created rupture, the very situation they were trying to avoid.  

But the question is whether the authors made all the important conclusions in this study.  True arrest disorders of labor are a risk for uterine rupture, particularly once pitocin has been added.  The authors are probably correct that true arrest of labor situation calls for extra-careful monitoring and a repeat cesarean may be indicated at some point. However, as noted, many women experience 'false' labor for days or intermittent early labor before settling into a steady labor patterns---why should this be any different for VBAC moms?  In Kmom's personal [non-expert] opinion, by defining 'dysfunctional labor' too strictly in early labor, this study established overly rigid guidelines that set up a scenario for increased rates of rupture.  Kmom's personal opinion is that this study is less about the dangers of arrest disorders than the dangers of aggressive pitocin use, especially in latent labor. 

Did most of these cases represent true arrest disorders of labor?  The authors note that in many cases pitocin was  actually started before the occurrence of 'dysfunctional' labor.  Is that truly an arrest disorder? In addition, many midwives believe that it is not unusual for women to be in the early stages of labor off and on for hours or even days.  Is that really a true 'arrest of labor'?

In fact, ACOG guidelines indicate that a diagnosis of lack of progress in labor should be made when "women [are] in the active phase of labor...and show no change in cervical dilation or descent of the fetal presenting part for at least 2 hours". Active labor is defined as dilation of 3+ cm in first-time moms, and 4+ cm in other moms  (Gifford, 2000).  Yet more than 2/3 of the women who ruptured had received pitocin augmentation when they were NOT in active labor. Thus the hospital may have created a situation ripe for uterine rupture in susceptible women either by requiring women in early labor to stay in the hospital, or to go onto pitocin simply because its definition of 'dysfunctional labor' may have been too rigid or their residents 'too busy' to adequately monitor labor progress.

Some doctors are very uncomfortable with VBAC moms laboring outside of the hospital, even in very early labor, since there have been occasional cases of ruptures occurring in very early labor (as there have been cases of it occurring before labor). The question is whether women in the early phase of labor have a very significant risk of rupture when pitocin augmentation is not present, and whether it's safe to be at home until a labor pattern is well-established.  Many midwives (and some doctors) believe the risk is more minimal at home than at a hospital that is ready to push pitocin use.  Although some doctors require that VBAC moms come to the hospital as soon as they feel contractions (or even require induction so that they can be monitored from the very beginning!), many others no longer require immediate hospitalization.  It would be interesting to see if the uterine rupture rate would be lowered under this policy.

Unfortunately many OBs now follow guidelines that state VBAC candidates must dilate 1 cm/hour or labor is 'dysfunctional' and 'needs' pitocin.  This may help explain why many later VBAC studies have a whopping 50-60% pitocin use rate (more than half of VBAC moms don't have uteri that work right?), and may explain at least partly the increase in rupture rates that have occurred in some studies over time.  It may also explain why some providers have much lower rates of VBACs than others; many terminate a TOL quickly at the first sign of a labor stalling, for fear of rupture and litigation.

Women with two or more cesareans in Leung 19993 were found to have an increased rate of uterine rupture (23/1165, or 2%).  The adjusted odds ratio for rupture after 2-3 prior cesareans was 3.8x.  It would have been interesting to see specific data on how much pitocin was used and at what stages in the women with multiple prior cesareans.  Without knowing this (and given the important questions on augmentation during early labor raised by the rest of the study), this seemingly alarming finding has to be taken with a grain of salt. It is still of definite concern, but must be placed in context. 

It's also important to note that the authors hastened to add that although the rupture rate was 2%, this also meant that "98% of the patients with two or three prior cesarean deliveries underwent trial of labor uneventfully."  Although the 2% rate is higher than after 1 cesarean and thus troubling, the study does not indicate what the rate of rupture in non-aggressively managed TOLs after multiple cesareans might be.  Nor do the authors recommend that trial of labor after multiple prior cesareans be eliminated; basically, they urge readers to keep the numbers in perspective.   Instead they concentrated their focus on prompt intervention when an arrest of labor is found.  

Cowan 1994 studied VBAC TOLs, both in women with 1 prior cesarean, and in women with 2-3 prior cesareans.  It found 5 ruptures out of 593 TOLs in the entire study, for a 0.8% rupture rate.  In one part of the study it says that 2 of 5 ruptures received pitocin, but in their 'Table 1: Characteristics of Patients with Uterine Rupture', 3 of 5 patients were noted as receiving pitocin (so this is the figure used in other parts of this FAQ).  

The VBA1C rate in the study was 419/518 VBACs (81% VBA1C).  4 of the 5 ruptures were in this group, for a 0.77% rupture rate in VBA1C.  All 3 of the ruptures that had pitocin were in the VBA1C group.

The VBA2C rate in the study was 56/72, or 77%.  There were also 3 women with 3 prior cesareans who had a TOL, all of whom had a VBA3C (100% rate).  If you combine the two groups, there were 75 TOLs in the VBA2+C groups, and 59/75 had a VBA2+C, for a 79% rate.  1 rupture happened in the VBA2C group, for a 1.4% rupture rate in the VBA2C group and a 0.0% rupture for the VBA3C group, or a 1.3% rupture rate for the two groups taken together.  

A 1.4% VBA2+C rupture rate in the study looks high, except that there's only one rupture, and it occurred in a woman with an 'unknown' scar type.  She did not receive pitocin, though she did have an epidural, and her labor was 17 hours long.  Her baby did fine afterwards.  The fact that she had an unknown scar means that it's possible that she had had a classical incision (which ruptures at higher rates).  However, because we cannot know for sure, this rupture gets classified into the VBA2+C group, and in such a small sample size, creates a high-looking rupture rate.  

Miller 1994 also found an increased rate of rupture in women with multiple previous cesareans, although this study did not examine the use of pitocin or its influence on rupture rates.  12,707 women who had a TOL from 1983-1992 were studied; overall, 75% had a VBAC and 0.7% ruptured (vs. 0.5% ruptures in the ERCS group).  

10,880 had had 1 prior c/s; 83% had a VBA1C and 0.6% ruptured.  1827 women had a TOL after 2 or more prior cesareans, and 75% had a VBA2+C, while 1.7% had a rupture.  This was nearly 3x the rupture rate of those with 1 cesarean.  This increase certainly looks alarming at first, and many authorities have concluded from this study that there is an increasing risk of rupture with each successive cesarean scar. However, it helps to look more closely at the data.  The rate of rupture was 0.6% in the VBA1C group, 1.8% in the VBA2C group, and 1.2% in the VBA3C group.  In other words, the rate of rupture did NOT go up in a linear fashion as the number of prior cesarean scars increased.  The 1.7% figure the study uses in its summary was actually an average of the VBA2C and VBA3C  figures.  

Women were noted to have induced or augmented labors in this study, but how many and at what point (or in what dosage) was not stated.  Given the concerns raised by the Leung 1993 study, this would be important information to know.  If the majority of the VBA2+Cs were induced or augmented aggressively in early labor, that might explain a higher rate of rupture in that group.  Since many doctors mistakenly believe that they can increase the rate of VBACs by inducing early, this might have been the scenario here.  However, without having this issue addressed in the study, it is impossible to know what role (if any) induction, augmentation, or other management issues played in the increased rate of ruptures in VBA2+C.  

Although the authors do not note this, it is again important to point out that even with a 1.7% rupture rate, more than 98% of VBA2+C labors proceeded uneventfully.  Furthermore, the authors do state that a TOL after 2 or more cesareans is a "reasonable option" with duly informed consent. The higher rate of rupture in the multiple cesarean group is definitely troubling (especially because this is the largest pool of VBA2+C candidates we have), but the data has somewhat limited use without knowing more specifics about laboring conditions and protocols.  The lack of controls for pitocin etc. use in the study is a strong limitation of it.

Asakura 1995 studied 302 women having a TOL  in Chicago between 1987-1991 after more than one previous cesarean.  The study accepted women with low vertical scars, prior uterine surgery for fibroids, and those with 'unknown' scars, as well as women with the usual low transverse scars.  The study lumped dehiscences and true ruptures together in their analyses; although the study found an increased rate of 'uterine wound separation' in women with multiple previous cesareans (2.0% vs. 1.1%), this difference did not rise to statistical significance.  Separating the rupture rate out from this combined data, women with >1 prior cesarean had a true rupture rate of 1.0% (vs. 0.5% in the VBA1C group, also not statistically significant).   Although it does not reach statistical significance, this increase in ruptures is troubling (though again it has to be noted that 98+% had an uneventful trial of labor).  

The study found that placenta accreta was found more often in conjunction with multiple prior cesareans (11.3x risk), causing a higher rate of hysterectomies in women with multiple cesareans (most were in the ERCS group; it wasn't related to a TOL).  They also note that two of the fetal injuries that occurred with ruptures were probably avoidable.  In particular, one rupture in a woman with 2 prior cesareans occurred after variable decelerations for 30-40 minutes and an abnormal scalp pH were noted, yet the woman was left unattended for 40 minutes!  This kind of 'poor obstetrical conditions' are responsible for a good percentage of problems that result from uterine ruptures, and many are preventable.  Being in a hospital, unfortunately, does not necessarily mean timely intervention will happen.  

Like most studies, this one has limitations.  The sample size, although larger than many, was not large enough for differences in uterine wound separations to reach statistical significance.  The study notes the need for research with larger samples sizes, particularly one with 1700 or more TOLs.  In addition, the study notes that pitocin augmentation and induction were used 'liberally', but they did not control for the effect of pitocin on rupture rates.  Again, given other data that shows that 'injudicious' pitocin use may play a major potential role in rupture, this is a major limitation.  

Caughey 1999 is the study that has many OBs alarmed.  It examined retrospectively the medical records of women with 1 or 2 prior cesareans who had undergone a TOL over a 12 year period (1984-1996).  It found a rupture rate of 3.7% in the 2 prior cesareans group that had a TOL (5 ruptures out of 134).  The rupture rate in the VBA1C group, in contrast, was 'only' 0.8% (31/3757).  After controlling for various variables (including pitocin use for once!), VBA2C was found to have 4.8x the risk of ruptures, definitely an alarming increase.  

However, the study does not examine when or how pitocin was used very closely.  It simply notes that equivalent amounts of pitocin were used in the VBA1C group (55%) and the VBA2C group (57%), and that levels of inductions were equivalent in both groups (19% each).   They did perform a multivariate logistic regression to compare the rate of rupture between the VBA1C and VBA2C TOL group, controlling for maternal age, epidural use, pitocin induction, pitocin augmentation, use of prostaglandin PGE2 gel, birth weight, gestational age, type of prior scar, year of TOL, and prior vaginal delivery.  Before this analysis, they had found an increased rupture risk for VBA2C of 4.5; after the analysis, the risk was increased slightly to 4.8x.  

Still, the question remains when pitocin was used.  Was it used more often to augment at early stages of labor, as in the Leung 1993 study?  Or was it truly used equivalently between groups?  At least the authors did a surface comparison, so we know the VBA2C group was not induced or augmented more often (something we don't know in the Miller 1994 study, for example).  However, given the strong correlation in the Leung study, it would have been MUCH more helpful to know more details about when the pitocin was used and in what dosage.  It also would have been interesting to have much more detailed information about each of the ruptures, to see if there were any common links or patterns in these women. And it would have been interesting to know if the rupture rates remained static and consistent, or if they increased over time.  Omitting these details makes the study more difficult to interpret.  

Another important observation is that this is one of a series of studies on VBAC and rupture etc. in 1999-2000, and their overall rate of rupture seems to be running fairly high in most.  This doesn't negate their findings, but you do have to wonder why their rupture rates are falling higher than most other studies'.  

The 3.7% VBA2C rupture rate in this study is worrisome.  Does this mean that all women with multiple prior cesareans have a higher risk for rupture overall, or simply that they may be more susceptible to rupture when pitocin is used so liberally? The high rate of pitocin use (more than 55%!) may indicate that women with multiple cesareans are more prone to rupture with pitocin use than women with only one scar, but that is certainly only speculation at this point.  More research is needed.

Other studies have had 50%+ pitocin rate without this high a rupture rate.  Yet this study's rupture rate was so much higher than most other studies (most of which fall at 1-2%) that it's possible it could be a statistical aberration.   But neither can it be dismissed as irrelevant.  What it basically calls for is more research into VBA2C, and preferably research with more details and analysis.  We need more data (both in women receiving pitocin and in women NOT receiving pitocin) so the real underlying rupture rates can be discovered and women counseled accurately as to their true risk.

Some doctors have used this study to justify excluding all women with 2+ prior cesareans from a TOL.  It's important to note that the authors don't do this.  They state that, "Although patients with 2 prior cesarean scars should be counseled differently from patients with 1 prior cesarean scar about their increased risk of uterine rupture and decreased chance of vaginal delivery in a subsequent trial of labor, on the basis of the evidence from this study and the existing literature, motivated patients may still wish to undergo a trial of labor.  Each patient and her provider must weigh the increased risk of uterine rupture against the benefits of vaginal delivery to determine the intended mode of delivery."  

Not exactly a ringing endorsement, but it does still support a TOL for the 'motivated patient'.   And of course, even if these stats turned out to be accurate (and note that this is the only study to have rupture rates this high), it's important to remember that 96% of the trials of labor after 2 cesareans proceeded uneventfully.  And nearly 2/3 of them had a VBAC as well, with the lower morbidity of a vaginal birth.  So although this latest VBA2C study is a bit alarming, it has to be kept in perspective as well. 

Burke 2000 is a very small study that examined the cases of uterine rupture that occurred at Pennsylvania Hospital over a period of 10 years (there were 25).  The next 'failed' VBAC after each rupture was selected as a control to compare the ruptures to, a common research technique but one that has some limitations.  The study looked to see if there were any identifiable risk factors in labor management that were common to the rupture cases.  They examined the role of maternal age, parity (number of pregnancies), labor management, and number of prior cesarean deliveries, but they found that patients were similar in these respects.  

There was a trend towards significance in labor management.  56% of the ruptures were induced vs. 36% of the controls, and 36% of the ruptures had PGE2 (prostaglandin gel) vs. 20% of the controls, but this difference did not rise to statistical significance, probably because of the small size of the study.  The important point of this study for our FAQ is that the number of prior low-transverse cesarean deliveries was not apparently associated with uterine rupture. 

Comparison of the Largest VBA2C Studies

Because many of the smaller VBA2C studies have less than 100 women having a TOL, and because most of these studies had no ruptures at all in them, it can be argued that they simply didn't have a large enough sample for ruptures to really start showing up.  Therefore, as a point of interest, a subanalysis of the studies with 100+ participants was done.  

Table VI: VBA2C Rupture Rates in Studies with 100+ TOLs

Study and number of TOLs Rupture Rate in TOL group with Transverse Scars Controlled for Pitocin Use?
Phelan 1987, n=159 0.0% ruptures no, but overall dehiscence rate was 2% w/out pitocin, 3% with pitocin
Phelan 1989, n=501 0.0% ruptures no, overall dehiscence rate was 1.4% w/out pitocin and 2.1% with pitocin
Flamm 1990, n=245 

(includes 1988 study in totals)

unstated; 1 rupture in woman with 2 c/s, prob. classical; author states rupture rate 'not increased in multiple c/s group', which means probably between 0.0-0.5% rate No, but in overall VBAC study, rupture rate was 0.1% without pitocin and 0.4% with pitocin
Leung 1993,  n=1165 2% ruptures 77% of all ruptures had pitocin, most in early labor; it is unknown how many of the 2+ c/s group had pit and at what point, which is important
Miller 1994,   n=1827 1.7%  (2 c/s and 3 c/s average) no; rupture was 1.8% in 2 c/s group and 1.2% in 3 c/s group (1.7% avgd.)
Chattopadhyay 1994, n=115 0.0% ruptures no
Asakura 1995, n=302 1% ruptures no
Abbassi 1998, n=130 1.5% ruptures most scar separations due to 'poor obstetrical conditions'
Caughey 1999, n=134 3.7% ruptures yes, but does not discuss at what point pitocin was used


Thus the large studies range from 0.0% to 3.7% rupture rate after 2+ cesareans.  If you group these larger studies by how many fall in each percentage range, the division is as following:

3 studies fell in the 0.0% rupture range, and 4 studies in the 1.0-2.0% rupture range.  The latter dovetails with the average rupture rate we found in this FAQ for ALL VBA2C studies together (as noted previously, about 1.4%).  As discussed earlier, pitocin was not controlled for in most studies, although its presence did seem to increase the rate of dehiscence and was present in the many of the ruptures found.  However, without specific details on how many of the ruptures had had pitocin (and at what stage in labor, and in what dosage), it is impossible to say for sure what the underlying true rate of ruptures would be in spontaneously laboring women not receiving pitocin or other drugs.  

Nearly all VBA2C studies had pitocin use, and a number of them had 50%+ pitocin use.  Very few VBA2C studies had little or no pitocin use to check VBA2C rupture rates without pitocin.  Hansell 1990 had no pitocin (0.0% rupture rate), but there were only 35 TOLs, much too small to draw conclusions from.  Saldana 1979 used pitocin only 'rarely' (0.0% rupture rate), but again there were only 38 TOLs, too small to generalize from.  The same is true for Farmakides 1987 (0.0% ruptures out of 57 TOLs, 9% pitocin use).  

It is very telling about the state of obstetrics that it is extremely hard to find VBAC studies with little or no pitocin use, and that in many studies, pitocin was used in half or more women. (Half of all the women had incompetent or inefficient uteri and 'needed' drugs to labor properly? Perhaps the problem is not so much women's uteri but doctors' definitions of 'abnormal' and 'normal' instead!)  

Regardless, it is important to note that any discussion of average rupture rates in VBA2+Cs usually means ruptures rates when pitocin is used liberally, instead of what the rupture rate would naturally be without artificial stimulants.  It is impossible to know at this point what the true rate of rupture is in spontaneously laboring women with multiple prior cesareans.

Kmom's Best Guess Estimates for Rupture Rates After Multiple Previous Cesareans

It's always risky to estimate rates of problems, and it's important to emphasize that Kmom is not a doctor, not a statistician, and certainly not an expert on research analysis.  However, after reviewing so much data, she has hazarded an informed 'guesstimate' of what rupture rates after multiple previous cesareans might be, based on the data that does exist on the issue.  Insert plenty of caveats, please, and remember that none of this constitutes medical advice!  These estimates may be totally off, but for what it's worth, this is Kmom's best guess.    

Kmom's best guess is that the rate of uterine rupture in a TOL after multiple prior cesareans when pitocin is used 'liberally' but still 'judiciously' is probably somewhere between 1% and 2%, with higher rates as pitocin use increases, especially for induction or in the early stage of labor.   Her intuitive guess is that pitocin use like this may particularly increase rates of rupture in women with multiple prior cesareans.  

Kmom's best guess is that the rate of uterine rupture in labors after multiple prior cesareans without pitocin (or other drug use) would probably be much lower (best guess between 0.4% and 1.0%, though there's not much data to base this guess on).  At this point, it is hard to know whether these rates would be increased over women with only 1 prior cesarean; Kmom's hunch is that they might be slightly increased as the number of prior cesareans increase, but probably not greatly unless pitocin/drugs or a high number of prior cesareans is present too.  Since there is very little data to base this on, however, it's important to particularly emphasize the speculative nature of this guess.  Again, no medical advice is implied here!

Does Pitocin Increase Risk of Uterine Rupture

As discussed above, use of pitocin (a synthetic form of the naturally-occurring labor hormone, oxytocin) remains controversial in VBAC TOLs.  In the 80s, most doctors tried to avoid its use or were extremely cautious in using it.  As a result, some women who might have been able to have a VBAC with the help of pitocin were not permitted to try and were forced to have an elective repeat cesarean instead.  By the late 80s, many prominent doctors were beginning to experiment with use of pitocin in these cases, and generally found that its use, carefully monitored and supervised, was relatively safe.  By the mid- 90s, use of pitocin was well-accepted in VBACs.

Unfortunately, increasing numbers of doctors then began using pitocin on VBAC moms with less and less discretion.  As the rate of  'active management of labor' and of labor inductions in non-cesarean mothers began to rise, it also began to rise in mothers with previous cesareans.  Some studies then began to show an increased risk of rupture when pitocin was used.  

For example, Rageth (1999) found that induction of labor was strongly associated with uterine rupture.  In this Swiss study, 17,613 TOLs after prior cesarean were analyzed.  The rate of rupture in all TOLs was found to be 0.40%, but the rate in TOLs that were induced was 0.65%.  The authors state, "This ratio is still low, but we believe that labor should be induced only if a clear indication is given."  

In addition, Zelop (1999) looked specifically at rupture rates in a large group of women with a trial of labor after one cesarean, and analyzed them by induction, augmentation, or spontaneous labor.  Women who labored spontaneously and had no pitocin augmentation had a rupture rate of 0.4%.  Women who labored spontaneously but had pitocin augmentation had a rupture rate of 1.0% (although higher, this did not reach statistical significance).  Women whose labors were induced with pitocin had a rupture rate of 2%, those induced with prostaglandin gels had a 2.9% rupture rate, and the small group that received both prostaglandin gel and pitocin had a rupture rate of 4.5%!  After controlling for variables, induction with pitocin was associated with a 4.6x risk of uterine rupture compared to no pitocin use.  That's pretty strong.  

In VBA2+C studies, Pruett 1988, Leung 1993, and Phelan 1989 found pitocin increased risk of dehiscence, and Flamm 1988 found that 2 of the 3 ruptures in its study had received pitocin as well.  Yet other studies such as Caughey 1999 did not find increased ruptures with pitocin use.  

When and how pitocin is used may make a difference.  Leung 1993 studied 70 cases of uterine rupture; they found that a whopping 77% of women who ruptured had received pitocin during the labor.  Most importantly, 2/3 of these women had received pitocin in the early (or latent) stage of labor, many at 2 cm or less. In addition, both of the ruptures in the Flamm 1988 study that had had pitocin were given it in early labor.  This raises the question of whether aggressive 'augmentation' of early (latent) labor is really appropriate in VBAC moms (see discussion above).  Furthermore, frequency and dosage excesses may also be associated with rupture; in the Zelop 1999 study, pitocin doses were noted to be increased every 15-20 minutes, which was much more frequent than many VBAC studies.  Although data is limited, it seems logical that pitocin use should be avoided whenever possible, or at least monitored even more carefully than usual if given in early labor or when the cervix is not ripe.  

But neither does this does not mean that pitocin can NEVER be used with a mother who has had previous cesareans.  A few doctors have begun to prohibit any use of pitocin in women with prior cesarean, which means that women with a true medical indication for induction or augmentation would not be permitted to VBAC but automatically relegated to an ERCS.  This is probably an overreaction as well, given that a number of studies have found that judicious use of pitocin is reasonably safe.  If the choice is between doing an elective cesarean and using pitocin, the data seems to support that pitocin can be used in most cases with very careful monitoring, although of course the decision must be made by the mother and her provider.  

The point is that pitocin use should probably not be routine in VBACs, just that it should be used VERY CAUTIOUSLY and only when absolutely necessary.  Many cases of pitocin-related rupture seem to be connected with 'excessive' pitocin, using it for induction of labor unnecessarily, using it aggressively during early or 'latent' labor or with an unripe cervix, using it in conjunction with multiple labor-induction techniques, or using it without adequate attention to monitoring and quick response to problems.  Further study is needed to examine the question of what constitutes 'reasonable' or 'judicious' use of pitocin.  However, in the meantime it seems logical that induction should be avoided unless absolutely medically indicated (as several authors advocate), dosage should err on the conservative side to be safer, and alternatives should be considered whenever possible.  For example, if a mother's labor seems to 'stall' out in early labor, alternatives such as therapeutic rest, walking or upright positions, change in maternal posture/position to assist rotation of a malpositioned baby, etc. should probably be considered before automatically resorting to pitocin augmentation.

It's especially important to note that VBAC moms who receive pitocin must be monitored very very carefully, as several studies have found that a number of cases of uterine rupture were caused by 'poor obstetric conditions', like inadequate monitoring, delayed access to emergency cesarean, or even ignoring  non-reassuring heart tones or the mother's intuition that "something was wrong".  Although uterine rupture usually does not result in death or serious damage to the baby, some cases have occurred where the mother was left unattended too long, or where a cesarean was not performed quickly enough once a problem was detected.  Several of these are noted in the VBA2C studies above.  Richard Porreco, M.D., commenting after the Hansell 1990 study, noted that "Perinatal morbidity (indeed mortality), with rare exceptions, should not occur in properly attended patients"  (emphasis his). VBAC moms should have attentive support and a plan for quick action if it is needed, and especially so if pitocin is used.  

In Kmom's non-expert opinion, pitocin probably can be used reasonably with VBAC mothers, when truly medically necessary and if used judiciously.  However, it is probably overused at this time, and may not always be supervised closely enough.  Poor obstetric judgment has probably caused a number of ruptures that artificially inflate the VBA2+C rupture rate; great care must be taken when using pitocin.  In Kmom's opinion, pitocin use probably does increase the rate of ruptures somewhat (and perhaps especially so in women with multiple prior cesareans), but these rates probably still fall within the range of reasonable risk with informed consent.  

The Influence of Other Factors on Uterine Rupture

Do other factors increase the rate of uterine rupture?  Many OBs believe that macrosomia, a prior cesarean for CPD, epidurals, twins, a low vertical scar, breast stimulation, a history of an unknown scar, or going past the due date predispose a woman towards uterine rupture.  In addition, some providers have questioned whether the use of other induction agents besides pitocin predisposes women to uterine rupture.  On the other hand, many midwives believe that a history of VBAC 'proves' uterine ability and may protect against future rupture.  Are any of these true?

As noted above, most studies find that macrosomia does not seem to increase the rate of uterine rupture (Flamm Birth After Cesarean, Flamm 1989, Leung 1993, Rageth 1999), although the rate might be higher if routine induction for macrosomia is used.  Most (but not all) studies have also found that epidural anesthesia is not associated with uterine rupture, although the combination of epidural anesthesia and pitocin use sometimes is associated with rupture (Rageth 1999).  Unknown uterine scar is also not generally found to be associated with the incidence of uterine rupture (Leung 1993).  Nor does a prior cesarean for CPD increase the rate of uterine rupture (Phelan 1987, Stovall 1987, Tahilramaney 1984, Leung 1993, Rageth 1999).  

Going past the due date (40 weeks) used to be thought of as possibly reducing the success rate and adding to the risk of rupture.  Zelop (2000, different study) found that rupture rate increased somewhat after 40 weeks (from 0.5% to 1.0% in spontaneous labor, from 2.1% to 2.6% in induced labor), although those in 'spontaneous' labor might still be receiving pitocin augmentation and it would be helpful to know if the pattern of dose and timing of augmentation/induction differed for those past the EDD.  The study does note that "the risk of uterine rupture does not increase substantially after the EDD."  Yeh (1984) found no increased rate of rupture in women who were postdates.  And Callahan (1999) found that even when women passed their due dates, the VBAC rates were still 66% (2 of 3).  They concluded that, "The patient and her family can be reassured that passing her due date does not alter the efficacy or safety of a trial of labor.  No change in counseling is warranted simply due to the completion of 40 weeks' gestation."

What about multiple gestations?  Does having twins after a prior cesarean increase the rate of uterine rupture?  This is a fear of many OBs and most do not 'permit' a TOL.  However, there HAVE been a few studies that had VBACs with twins (Wax 2000, which had an 83% VBAC rate with twins, Miller 1996 describes 92 TOLs with twins with no resulting ruptures, Odeh 1997 documents a 17/21or 81% VBAC rate with twins and no ruptures--- references not listed below due to space limitations).  In addition, several twin VBACs were noted in the studies analyzed for this FAQ, notably Veridiano 1989 (2 twin VBACs), and Abbassi 1998 (in the second of two 1998 studies, it found a 75% twin VBAC rate).  This is not enough data to determine the rates of rupture during Twin VBAC, but it's a promising start.  Although  more research needs to be done on this issue and it is not possible to conclude what the rate of rupture might be for sure, VBAC with twins has happened.  It is not easy to find an OB who will consider a VBAC TOL when twins are present, but it is possible.  

What about low vertical scars?  Because the rate of rupture is higher after a full vertical ('classical') cesarean, many OBs in the past have shied away from a TOL with a low vertical scar (an up-down scar that is limited to only the lower uterine segment, not the upper segment which is more prone to rupture).  There are a number of recent studies (which are too numerous to cite here) on VBA1C with a low vertical incision, and they have generally found that uterine rupture is not increased with a low vertical scar, as long as the incision did not extend into the upper uterine segment.  Most OBs currently do not consider one low-vertical scar a contraindication to a TOL, although ACOG neither endorses nor condemns it.   

In addition, there are several VBA2C studies that have had a few TOLs in women with 1+ low vertical scars.  Novas 1989 and Pruett 1988 all had a few low vertical scars among their TOL groups.  In addition, Stovall 1987 had 58 TOLs after 1 low-vertical c/s (88% VBAC rate), 5 TOLs after 2 low-vertical c/s (100% VBAC rate), and 1 TOL after 3 low-vertical c/s (100% VBAC rate).  There were no ruptures reported in any of these studies in those with transverse or low vertical scars.   The data is quite limited, but given that VBA1C with a low-vertical scar does not seem to present a higher rate of rupture, a TOL after 2 or more low-vertical scars is probably reasonable also, as long as the incision did not extend into the upper segment of the uterus.

However, it is important to note that on all of these issues (macrosomia, unknown scars, post-term pregnancy, twins, low vertical incisions, even VBA2+C itself), the numerical sample on the available studies are not large enough for statistical certainty, despite the considerable evidence that has accumulated for some of these categories.  Because of the current VBAC backlash and climate of fear over being sued, the latest ACOG bulletin (1999) chooses to cover the organization by stating that, "Although success has been reported in some series, continuing analysis of the risk of adverse outcome in necessary before VBAC is routinely adopted in these circumstances."  It is certainly reasonable to ask for more data, but the problem is that these studies are not even being undertaken very often. Denying women with these circumstances a TOL in the meantime means that great numbers of women would end up with probably unnecessary repeat cesareans, with all the attendant risks those entail (see below).  

Although statistical certainty is not possible and more data is always useful, the weight of existing evidence on many of these is fairly considerable, and a trial of labor with duly informed consent about possible risks and limited statistical size in assessing these risks is usually a reasonable option.  That doesn't necessarily mean it is or is not  the right option for you, however.  If you fall into one of these categories, read up on the studies and make your own decision as to whether a TOL is reasonable.  If you decide to have a TOL, you can then find a provider that is open to it (midwives generally offer a TOL in more circumstances than many OBs and are generally more responsive to research citations, but some OBs will support a TOL in these situations as well). Many women HAVE had VBACs (and even VBA2+Cs) with macrosomia, unknown scars, a post-term pregnancy, with twins, or with low vertical incisions, but of course no one can promise any individual complete safety with either a TOL or an ERCS.  Both carry potential risks, but the risks do not seem unreasonable either way. Each woman and her provider has to decide what's reasonable and best in her situation. (Note: If you are considering a TOL in one of these scenarios, you can read the VBAC stories and resources listed in the accompanying FAQ on this web site (VBA2C Stories) for inspiration.)

On the other hand, other induction agents such as prostaglandin gels (PGE2, trade names Prepidil or Cervidil) and misoprostol (PGE1, trade name Cytotec) have been found to be associated with increased rupture rates in some studies.  Such products should be used with great caution, if at all, and preferably only when truly necessary.

Although several studies have found low rates of rupture with PGE2 products, there ARE cases on record that document uterine rupture solely with PGE2 prostaglandin gels, or particularly when prostaglandin gels are used with other methods.  A very recent study (Ravasia 2000) found strongly increased rates of rupture associated with PGE2 gels (2.9% vs. 0.45%, relative risk 6.4x), although this may represent the risk of inducing with an unripe cervix as well.  Zelop (1999) found a 3.2x risk for induction with PGE2 gels, although this did not quite rise to statistical significance.  However, when considering the group that received both PGE2 gel and pitocin, the rupture rate rose strongly to 4.5% (although the sample size--and therefore statistical power---is small in this group).   So it is unclear how much risk is attributable to PGE2 products, how much from trying to force labor with drugs when the cervix is unripe and not ready for labor, and how much from using too many types of labor-'enhancers' together.

This possibility is noted in the AIMS Journal (Journal of the Association for Improvements in the Maternity Services [a U.K. organization], volume 7, #1, Spring 1995), where it is stated that:

During the last few years there has been a noticeable increase in cases where the uterus has ruptured during labor.  Commonly, the woman has had a previous cesarean.  In almost all the rupture cases we see, the woman has had prostaglandin pessaries or gel inserted into the vagina.  This has the effect of both softening and ripening the cervix and causing contractions, but the amount of time this may take and the strength of the response can vary.  A second, then a third dose can be given before the previous dose has been given full opportunity to work.  Then an oxytocin drip is added, which further stimulates the uterus.  The woman is given an epidural for the pain this causes, but the epidural can mask or reduce the pain of rupture.  The combination of scarred uterus, prostaglandins and/or oxytocin requires constant monitoring from staff.  Training or retraining of staff on recognition of signs of possible rupture is recommended.  Prostaglandins and/or oxytocin should be used only when really necessary on women with scarred uteri or women at other risk of rupture.

In other words, it may not be that prostaglandin E2 products are the problem, but that forcing labor before the cervix is ripe or using too many induction agents (especially in a short time period) and 'overloading' the uterus may predispose it towards rupture. If a woman is given PGE2 products several times (every 3-4 hours is common; some do it every hour), and then add in pitocin on top of that (doses are commonly increased every half-hour to hour, and in some studies are increased every 15-20 minutes!), then it would be no wonder that many women's uteri get overstimulated and tend towards rupture.  

It may not be that PGE2 products make women prone to rupture, but that the dosage, frequency, and combination with other products is the real danger.  More research is needed.  However, in the meantime, it seems sensible to avoid this scenario whenever possible, and when an induction is truly medically necessary, to do so with a less aggressive dosing schedule, heightened awareness of rupture patterns,  careful attention to monitoring, and the ability for quick action if needed.

Misoprostol (Cytotec) is another type of prostaglandin (PGE1) that has become very popular for inducing labor these days, but this is a product that should probably not be used commonly for VBACs.  Its advantages include that it is much cheaper, that it ripens the cervix and brings on contractions, and tends to work faster than many other methods.  However,  it also usually increases the rate of uterine hyperstimulation, sometimes fetal distress, and possibly rupture, while not usually lowering the cesarean rate.  It is also not approved for use in pregnancy; it was originally an ulcer drug that is being used off-label for labor induction.  In fact, the company that makes it has sent letters warning doctors that it is not approved for use in pregnancy (to cover the company in case it gets sued).  Although this puts a bit of a damper on some of the great enthusiasm shown in the obstetric community for Cytotec, it undoubtedly will not stop its use or even slow it much. Doctors in particular like how much cheaper it is to use, and how much faster labors go with it.  Unfortunately, most women on whom it is used are unaware that adequate testing of it in pregnancy has not taken place, and that it has strong risk of hyperstimulation. In other words, most doctors are using it experimentally and without adequate informed consent.

Although data is limited, the initial studies of Cytotec in VBAC shows a strongly increased rate of uterine rupture. For example, a prospective, randomized trial on Cytotec in VBAC moms was abandoned after 2 of 17 women (12%!!) experienced a rupture (Wing 1998).  Another study retrospectively found a rupture rate of 6.3% with Cytotec compared to 1.1% with pitocin (Hill 2000), and a literature review by Plaut (1999) found a 5.6% rupture rate when labor was induced with Cytotec (vs. a 0.2% rupture rate without it).  Obviously, this is much higher than the rates normally found even with other induction methods.  Although a few OBs are conducting limited trials still, and a few midwives persist in using Cytotec in much lower or less frequent dosages, most providers have been scared away from its use with VBACs.  Since Cytotec has been noted to increase the incidence of uterine rupture even among women without prior cesareans, most providers feel that it is not appropriate for use in VBACs.  

Other induction techniques and products are less-studied so an accurate evaluation of relative risk is impossible.  The Ravasia 2000 study mentioned above did find that an intracervical Foley catheter (which dilates the cervix mechanically) had a rupture rate of 0.76% (vs. 0.45% in the non-induction group).  Kmom is aware of no scientific data on the use of herbal induction products such as the blue and black cohoshes, but it is probably sensible to use these (like other induction techniques) with great caution, if at all  (and they are contraindicated in the presence of borderline or high blood pressure, as they can increase blood pressure). 

On the other hand, breast stimulation is a natural alternative for increasing the body's own oxytocin levels, although most OBs are certainly more comfortable with a pharmacological approach!  Some OBs worry that it can produce overly strong contractions, but it is ironic that these same OBs don't worry about the overly strong contractions that pitocin can create, nor do they tell women to abstain from sex or nipple stimulation during pregnancy.  There is little data on its safety after prior cesarean, although one study (Segal 1995) found it to be safe and efficacious in VBAC women.  Although some will rule out its use, many midwives (and some OBs) are comfortable with breast stimulation used judiciously.  

Evening Primrose Oil (EPO) contains prostaglandin precursors that help soften and ripen the cervix for labor, but does not bring on labor contractions.  There is no data on its use in women with prior cesareans, mostly because OBs refuse to study it.  Most OBs are not comfortable recommending it because of this lack of official data, yet will not study it in order to get data, creating a difficult Catch 22 situation. Many midwives feel comfortable using it since it has years of positive anecdotal use behind it and is not seen to induce labor at all.  However, a few home midwives strongly believe that no drugs of any sort should be used on women with prior cesareans, not even EPO.  The choice will depend on the philosophy of your provider and the medical circumstances of your case.

If it is important not to go 'overdue' in your pregnancy or if you face a strong possibility of induction for legitimate medical reasons, your midwife or other provider may suggest 'ripening' the cervix ahead of time with EPO (keep in mind it takes at least 1-2 weeks for it to be effective).  Since a number of ruptures seem to occur when the cervix is unripe yet forced into labor, some providers reason that ripening it ahead of time will increase the chance of VBAC success, and may lessen the chance of rupture.  Sex (including nipple stimulation and orgasm) can also help produce natural oxytocin, and semen contains prostaglandins to help ripen the cervix, so these may also be suggested to help ready the body for labor ahead of time.

Prostaglandin gels are also used for ripening, but over a much shorter period of time, and they can bring on labor contractions.  Given particularly the problems that may occur when PGE2 gels are added to other induction drugs over a short period of time, some providers see Evening Primrose Oil, sex, and/or nipple stimulation as a much more gentle and incremental way of ripening the cervix without bringing on labor.  On the other hand, you or your provider may decide that no intervention at all is the wisest course.  Consult your provider.  

Does this mean that labor can never be induced in a woman with a prior cesarean?  No, of course not.  Many women with prior cesareans are induced and do fine.  If there is truly a medical indication necessitating induction, many providers feel it is still a reasonable choice to choose induction over ERCS. However, it is not a choice that should be undertaken casually or without regard to potential problems.  There is substantial research that induction does probably increase the risk of rupture somewhat, and early and aggressive augmentation may also increase risk as well.  In particular, aggressive frequency and high dosage (especially with multiple agents) on an unripe cervix may be particularly risky.  On the other hand, even in inductions, rupture is still not all that common.  If your situation truly necessitates induction, there may be ways to lower the risk somewhat, depending on the specifics of your case.  And of course, it is extremely important during an induction to have an attentive and knowledgeable staff, careful monitoring, and a plan for quick action if necessary.  That way if problems did occur, it is likely that their effects could be minimized.  As always, consult your provider.  

Finally, does a prior vaginal birth protect against uterine rupture?  3 studies examined this question.  Leung 1993 found that prior VBAC did not protect against rupture in subsequent pregnancies (although the study had very high rates of pitocin use), whereas Caughey 1999 found that women with prior vaginal births (VBAC or vaginal births prior to cesarean) had about 1/4 the rate of uterine ruptures.   In a further analysis, Zelop (2000) found that those with prior vaginal births had about 1/5 the rate of ruptures (0.2% rupture in the group with at least 1 prior vaginal birth, vs. 1.1% rupture in the group with no prior vaginal birth).  Furthermore, in the group of women with 2 or more prior cesareans, the rupture rate was 2.5% in those with a prior vaginal birth, vs. 3.9% in those with no prior vaginal birth.  Because of the small sample size in this part of the study, this difference did not rise to statistical significance, but the authors noted that women with multiple cesareans plus prior vaginal births had a 40% lower risk for rupture.  The study noted that it had previously shown that induction by pitocin carried 4.6x the risk for rupture in a related study; it would be interesting to know more details of the ruptures that occurred in the multiple c/s group.   

Most providers seem to believe that a prior VBAC tends to make rupture in a later pregnancy less likely, but that cannot be guaranteed, of course.  Other factors will come into play, such as grand multiparity (women with 5 or more births tend to have a higher risk of rupture, even without previous cesareans) and pitocin use (pitocin use--especially early in labor--may increase rupture rates, see above).  Zelop 2000 noted that 2 of the ruptures found in the VBA1C group occurred in women who had both had 2 prior VBACs (wonder how much pitocin these women had?).  So although prior vaginal birth may be protective against rupture, it is not a guarantee, and the overall combination of factors during the labor is probably more important.  

Minimizing the Risk of Uterine Rupture

Given all of these factors that may or may not add or take away from the risk of uterine rupture, how can YOU minimize the risk of uterine rupture happening to you?  This is a matter of opinion, since authorities certainly don't completely agree on the subject.  However, the data certainly seem to have a few consistencies.  Remember, however, that this is not medical advice, and you should always consult your provider.  

To minimize the risk of uterine rupture in a TOL, it seems logical from the data to consider the following:

Jackie Mawson, writing on induction and VBAC at, states that:

If we wait until our baby's ready to labour, then our cervix will be softened and ready to dilate, and our baby should hopefully be in the correct position for a problem-free labour.  If we rush this natural process and initiate labour prematurely, then the artificial induction may cause strong uterine contractions against a cervix which is not ready to start dilating, increasing uterine pressure, which could lead to uterine rupture, especially when the uterus already has a prior cesarean scar.  It has been suggested that our baby gets into the correct position just prior to the onset of natural labor.  So what happens if we choose a labour date, instead of nature?  If our baby is in the wrong position then we are going to have big problems birthing our baby vaginally."

There are probably many things that can be done to maximize your chances for a VBAC and minimize your chances for rupture or other problems, but avoiding induction, routine interventions, and assuring that the things like baby malposition or emotional dystocia will not stall labor unnecessarily are probably at the top of the list.  However, it is up to YOU to educate yourself about these choices, advocate for yourself and your baby, consult with your provider, and choose the course that seems most sensible for your situation. 


The specter of fetal death due to uterine rupture is a fear that hangs heavy over every c/s mother.  Although most VBAC mothers do not rupture, although choosing ERCS does NOT eliminate the risk of uterine rupture, and although most ruptures that do occur usually do not result in fetal death, the fear of this worst-case scenario is one that is not easy to escape.  It is a real, albeit small, risk, and it is important not to gloss over this small but definite risk.  Although it is the previous cesarean that really creates the risk, fear of uterine rupture and fetal harm is a definite cause of anxiety for many post-cesarean women.  This fear colors many of the decisions made for any pregnancy after a prior cesarean.

Many studies have looked at the risk of uterine rupture and potential fetal harm and found that a TOL is an absolutely reasonable option.  Rosen (1991) found no increased rate of uterine dehiscence/rupture with a TOL, no increased rate of deaths, and lower rates of maternal morbidity.  Mozurkewich and Hutton (2000) found a slightly higher rate of rupture and fetal death in the TOL group (they did not analyze for pitocin etc. use), but a lower rate of maternal morbidity such as need for transfusions, febrile morbidity, and hysterectomies.  Furthermore, they pointed out that while the rupture etc. risks were slightly higher in the TOL group, the absolute risk was really quite small for either group, and that either a TOL or an ERCS remained a reasonable option.  

However, neither of these meta-analyses did a subanalysis for the group with multiple prior cesareans. So is a TOL after 2 cesareans also a reasonable option?  As noted, the rate of rupture after multiple prior cesareans seemed to be no higher  than after one prior cesarean in the original VBA2C research of the 1980s and early 90s (as noted by Roberts 1991), and many authors (and ACOG) concluded that VBA2C was indeed a reasonable option. However, later research seemed to show somewhat higher rupture rates in the VBA2C studies.  Because of this, ACOG has sounded a note of greater caution on VBA2Cs, and the current VBAC backlash in the USA has especially impacted VBA2C TOLs.  So is a VBA2C still a reasonable option?

The limit of most VBA2+C research is that almost no studies control for pitocin/other drug use, and this may well be an important factor.  Although the jury is still out, uterine rupture rates may be somewhat higher in VBA2C, particularly when pitocin or multiple induction agents are used.  Nearly all VBA2C studies analyzed used pitocin etc. quite liberally, often for 50% or more of their participants. (!)  Thus, it is impossible to know for sure what the true underlying rate of rupture in VBA2C may be.  Although hard data is lacking, it seems likely that the average VBA2C rupture rate of 1.4% found in this FAQ could probably be significantly lowered by inducing less, inducing only when the cervix is ripe when induction becomes important, and using obstetric drugs and interventions much less (and much more judiciously when they are used).  Yet it is still possible that even without lots of pitocin and other drugs, the rupture rate for VBAC after multiple cesareans may still be slightly higher than after VBA1C.  If so, is this a reasonable risk for mothers and their providers to assume?

This is a judgment that each mother must decide for herself.  She must weigh the potential risks of a TOL, but she must also remember that ERCS does not eliminate the risk of uterine rupture completely, and that ERCS also carries small but also very significant risks (particularly if she wants more children, see below).  She must take an honest look at her own desires and fears and what motivates them, and weigh the relative benefits and risks for her own circumstances.  She must listen carefully to the counsel of her provider, but also remember that providers differ markedly in their support of VBAC and knowledge of VBAC research, and that some VBAC counseling is not always accurate.  In short, she should check the research, consult several providers to seek a variety of opinions, weigh the potential risks and benefits of both options, consider the circumstances of her own particular case, and then check her own internal intuition and decide what is the right choice for her and her baby. 

What about from a public health viewpoint?  Should providers support a TOL after multiple prior cesareans? First, it's important to keep the wide variety of rupture rates in perspective. Faridi (1999) did a literature review on trials of labor after 2 previous cesareans, and found that the rupture rates generally varied between 0% - 2.8%.  This study concludes, however, that "Maternal and fetal outcomes in women who have had multiple previous sections do not differ from those in women after ordinary cesarean section...these women should be treated no differently than those who have had only one cesarean delivery."   Other studies support a trial of labor after multiple cesareans, but under more limited circumstances and with careful supervision.  Although Caughey's recent study raises some concerns for some doctors, even Caughey's study supported a TOL after 2 c/s, and ACOG also continues qualified support for VBA2C.   

Rupture rates vary from study to study and it is impossible at this point to state with certainty what the underlying rupture rate would be with lower rates of induction and more judicious use of pitocin. This makes it difficult to gauge the true risk.  However, even with strong use of labor drugs, rupture rates are usually within the levels of reasonable risk for an informed patient and an attentive and conscientious provider, and ACOG still continues qualified support for VBA2C.  It is especially important to note that almost all of the studies reviewed supported a trial of labor after 2 previous cesareans for the 'motivated' patient.  Choosing to pursue a vaginal birth after 2 previous cesareans CAN be a reasonable choice, both from a personal viewpoint and from a public health perspective.


VBAC After 3 or More Cesareans

So what about VBAC after more than 2 cesareans?  Is that a reasonable choice?  This is more difficult to say because there is so little data available on VBA3+C.  Women HAVE had VBACs after 3 or more cesareans, but most documentation of this comes from anecdotal birth stories on the internet and in the lay VBAC literature like Silent Knife, Natural Childbirth After Cesarean, The Vaginal Birth After Cesarean Experience, etc.  (See VBA2C Stories for exact references.)  Unfortunately, although many women have had VBACs after 3 or more cesareans, documentations of this in the medical literature are harder to find.   Although the sample sizes are generally extremely small, some cases can be gleaned from the VBAC literature.  The following are some of the studies that report on a trial of labor in women with 3 or more previous cesareans.  

Some studies did have passing mention of women with 3 or more previous cesareans in their research group, but did not specify outcome for them separately (i.e., Granovsky 1994).  Therefore, their stats could not be figured into the totals here.  The only studies listed here specify at least partially the outcome of the group with 3 or more previous cesareans.  Also, studies before 1979 were omitted because the laboring conditions and protocols were so different then that comparisons are difficult.  Too many of those studies involve women with classical cesareans (which have a higher rupture rate), heavy use of drugs, forceps, and other highly interventive protocols which obscure the risk.

The following studies did specify trials of labor with women with 3 or more previous cesareans, and did document at least partially their outcomes:

Saldana 1979 -  Notes 38 TOLs in women with 2+ cesareans, and 22 had VBACs for a rate of 58%.  Of the 22 VBACs, the authors note that 4 were VBA3Cs.  There were 0 ruptures or dehiscences in the TOL group.

Martin 1983 - Notes 19 TOLs in women with 2+ cesareans, including 6 trials of labor in women with >2 cesareans.  3/6 had a VBA3+C (50% VBA3C rate).  There were no ruptures or dehiscences in any of the multiple cesarean mothers who had a TOL; one was found in a woman in the ERCS group.

Tahilramaney 1984 - This study showed an increased rate of dehiscences with an increasing number of uterine incisions, but the difference did not reach statistical significance.  There was a rate of 2.6% after 1 c/s, 3.0% after 2 c/s, and 7.5% after 3 cesareans.  However, again, these did not reach statistical significance, nor did it appear that these dehiscences were clinically relevant (i.e. true ruptures) although more information is needed to know for sure.  Distinctions between dehiscences and ruptures were not clearly made at all; the summary reads as though there were 5 ruptures out of 836 total patients in the study; most of these appear to be in the elective repeat cesarean arm of the study and if they appeared in any of the multiple c/s patients, it was not specified. So the exact status of rupture rates in multiple cesarean mothers cannot be determined, but the authors do conclude at the end that "the number of previous C/Ss...appear to have little, if any, prognostic significance for uterine rupture."  

Farmakides 1987 -  There were 57 TOLs in women with 2 or more cesareans.  39 of these were in women were 2 previous cesareans, and 18 were in women with 3 previous cesareans.  Of the 57 in the total group, 77% had a VBA2+C, but there's no way to tell what the VBAC rate was in the 3 previous c/s group.  However, there was only one dehiscence and no ruptures at all in the overall TOL group, which means that there were no ruptures in the 3 cesarean group.  It is unknown how many previous cesareans the woman with the dehiscence had.

Stovall 1987 - There were 6 VBA3Cs in women with low transverse scars in this study (plus 1 in a woman with  3 low vertical scars) for a 100% VBA3C rate.  There were no ruptures in the multiple previous c/s TOL group.  

Phelan 1987 - There were 1796 women who underwent a trial of labor in this study; 10 of them had had 3 previous cesareans.  9/10 had a VBA3C for a success rate of 90%.  The overall rupture rate was 0.3% for all TOLs, and the authors did not specify the rupture rate by amount of previous cesareans.  However, they did state that ruptures were not increased in the group with multiple previous cesareans.

Pruett 1988 - 55 TOL after 2+C; 51 after 2 c/s and 4 after 3 c/s.  2/4 women with 3 previous cesareans had a VBAC, for a success rate of 50%.  One of them did have a scar dehiscence, but she was in her 7th pregnancy (grand multips are known to be more at-risk for rupture) and the type of incisions she had were unknown.  She had had erratic prenatal care, and pitocin was also used in her labor.  Baby was born vaginally and was fine; the scar dehiscence was only noted afterwards with manual exploration after bleeding.  She choose to have a hysterectomy anyhow for sterilization.  Because the mother was a grand multip and had also had oxytocin for her labor, this dehiscence cannot be said reliably to have been due to 3 previous scars, but neither can it (or a combination of the 3 factors) be ruled out.

Flamm 1988 - As part of a much larger study, 89 women had a TOL after 2 previous c/s.  Of these, 7 women had a TOL after 3 previous cesareans.  5 had a VBAC (71% VBA3C).  None had any ruptures.  

Veridiano 1989 - Although the concentration was mostly on VBA1C, this study did document successful VBACs in women with multiple previous cesareans---14 VBA2Cs, 4 VBA3Cs, 2 VBA4Cs, and 1 VBA5C.  Success rates were not given for each category separately; the overall VBAC rate for all VBA2+Cs was 84%.  Authors state there were 'no complications' for the multiple cesarean TOL group, so presumably there were no ruptures or dehiscences in this group. 

Novas 1989 - 36 TOLs in women with 2+ c/s, including 9 TOLs in women with 3 or more previous c/s.  8/9 had a VBA3+C for a success rate of 89%.  This compared to a success rate of 78% for VBA2C.  There were no ruptures in any of the multiple cesareans group.  

Hansell 1990 - 35 TOLs in women with 2+ c/s, including 6 TOLs in women with more than 2 c/s. 5 women with 3 previous c/s had a TOL; 3/5 or 60% had a VBA3C.  1 woman with 4 previous c/s had a TOL, she had a VBA4C (success rate of 100%).  In the TOL group, there were 2 asymptomatic windows or 'thinning' of scars with no complications or problems; there were NO ruptures in the TOL group (the elective repeat cesarean group had a rupture before term).  

Cowan 1994 - 75 TOLs in women with 2+ c/s, including 3 TOLs in women with 3 prior c/s.  All three women had a VBAC, for a 100% VBA3C rate.  There were no ruptures in the 3 c/s group.

Miller 1994 - The largest study of VBA2+C rates around.  There were 1827 TOLs in women with more than one previous c/s, including 1586 in women with 2 previous c/s and 241 in women with 3 or more previous c/s.  These offer some substantial study sizes to evaluate.  In this the rupture rate (1.7%) does appear to go up as uterine incisions go up when averaged; when separated out, the rupture rate was 1.8% for VBA2C and 1.2% for VBA3+C, so it does not continue to go up as the number of previous c/s got higher, which weakens the conclusion that it must be due to the number of previous incisions.  That rate is double that of the 0.6% rate for VBA1C; the overall averaged rate is ~3x higher.  However, no attempt was made to control for oxytocin use; if more VBA2+C moms were induced or heavily augmented, that could explain a higher rate of rupture for them.  This is a major weakness in the study.  The authors do conclude lukewarmly that offering a TOL to women with 2 or more previous cesareans is a 'reasonable option' but that it is best kept only for 'motivated' patients.  They also emphasize the decreased VBAC success rate among those with multiple cesareans, but this is greatly overstated, given that 75% still achieved VBA2Cs (79% of those with 3 or more c/s!), a rate higher than many VBA1C studies.  

Table VII:  Miller, 1994 "Vaginal Birth After Cesarean: A 10-Year Experience" 

# of previous c/s number of TOL VBAC success rate rupture rate
VBA1C n = 10, 880 83% 0.6%
VBA2C n = 1586 75% 1.8%
VBA3+C n = 241 79% 1.2%
VBA2+C (averaged) n = 1827 total 75% averaged 1.7% averaged


Summary of VBA3+C Studies

Of all of the studies listed above, there were 239 VBA3+Cs.  Unfortunately, only a few studies specify the exact VBAC success rate among those with 3 previous cesareans.  Of these, most had excellent success rates, although in all but one of the studies the numbers were quite small, which limits the power of the conclusions that can be drawn.  The success rates follow.

Table VIII: VBA3+C Success Rates

Study/Year VBA3+C Success Rates VBACs/TOLs
Martin, 1983 50% VBA3+C n=3/6
Stovall, 1987 100% VBA3+C n=7/7
Phelan 1987 90% VBA3+C n=9/10
Pruett, 1988 50% VBA3+C n=2/4
Flamm, 1988 71% VBA3+C n=5/7
Novas, 1989 89% VBA3+C n=8/9
Hansell, 1990 67% VBA3+C n=4/6
Cowan, 1994 100% VBA3C n=3/3
Miller 1994 79% VBA3+C n=190/241


If you add up the numbers of all the VBA3C studies for which we have specific success rate data, there was a total of 231 out of 293 VBA3+Cs.  That averages out to a total VBA3+C success rate of 79%, which is pretty darn good!  In fact, that is a higher rate of success than many VBA1C studies and even much VBA2C data.  

This good success rate probably reflects that women who go for a VBAC after this many cesareans are probably carefully selected by their providers, carefully select their providers, are probably highly motivated, and probably prepare very carefully, four things which might well lead to a higher success rate.  It's possible that the numbers could be skewed because they are so small, but even so, a 79% success rate is excellent.

Some women are still told that VBAC after 3 or more cesareans is impossible, that the rupture rate would be too high, or that there is NO data on this situation and therefore it would be too risky to try.  It is simply not true that VBA3+C is impossible; it has been documented at least 231 times, and the number is certainly higher since other studies mention VBACs with 3+ previous cesareans but don't stratify results more specifically to enable us to add them to the success rate totals.  

It's also notable that the rupture rate in most of these VBA2+C studies was 0.0%, although this is probably partly because of the small sample sizes.  In the studies for which we have uterine rupture rates specified in VBA3C TOLs, there were 4 ruptures out of 312 TOLs, for a rupture rate of 1.3%, about the same as the VBA2C rate. (Do note that not all studies specified both success rates and rupture rates for VBA3+C, so numbers are a little different than in the table above).  As with VBA2C, it is important to note that this rate reflects the rupture rate when pitocin and other drugs are used quite liberally, and it is impossible to know for sure what the true underlying rupture rate would be without pitocin or other drugs (or very minimal use of them).  

Most of the VBA3+C ruptures are from the Miller 1994 study, which does show a higher rate of ruptures (BUT did not control for oxytocin use, which may have increased the rate). A definitive evaluation of the VBA3+C possible risk cannot be done at this point, because the numbers are too small.  Although multiple previous cesareans may increase the rupture rate some, it does not appear so far to do so excessively, and is certainly a risk that a mother and her provider might assume with suitable precautions and duly informed consent.  

In recent prior practice bulletins on VBAC, ACOG did not rule out a trial of labor after more than 2 prior cesareans.  However, in the July 1999 practice bulletin on VBAC, the organization takes a step back.  It lists as candidates for a trial of labor women who have had "one or two prior low transverse cesarean deliveries."  Citing the Miller 1994 study, it states that "Women who have had two previous low-transverse cesarean deliveries also may be considered for a trial of labor, but the risk of uterine rupture increases with the number of previous uterine incisions," and women should be warned accordingly.  

On the other hand, in the section on contraindications for VBAC, women with 3 or more cesareans are not specifically forbidden from a TOL either.  ACOG basically hedges its bets by endorsing offering a TOL for women with one prior cesarean, 'allowing' a TOL for women with two prior cesareans (with the proper warnings to the woman), and not taking a specific stand for or against a TOL in women with more than 2 prior cesareans.  As noted previously, it states that, "There has been a tendency to expand the list of obstetric circumstances under which VBAC may be appropriate.  These include multiple previous cesarean deliveries...Whether trial of labor should be encouraged for patients with these obstetric controversial.  Although success has been reported in some series, continuing analysis of the risk of adverse outcome is necessary before VBAC is routinely adopted in these circumstances."

Although data is limited on this issue and some providers still block VBA3Cs by citing lack of data on which to gauge possible risk, there certainly IS some data on this situation.  However, the numbers are less than definitive because most major institutions have not 'permitted' trials of labor in women with multiple cesareans, or limited most study to those women with only 2 previous cesareans.   Obviously, the only way to GET more data is to study the situation (with informed consent) instead of ignoring it or just declaring it impossible.  As long as major research centers refuse to study the issue seriously, definitive data (with enough women studied to give the data sufficient power to be conclusive) will be limited.  But that should not prevent strongly motivated women with supportive providers from trying VBA3+C, as long as there is adequate informed consent.  Many providers do believe that there IS a place for VBA3+C on a smaller-scale, fully informed basis, although it generally has its strongest support among midwives.

Although the numbers are generally small, VBA3+C has occurred.  It is documented in anecdotal and lay VBAC literature, and it is also documented in the medical literature.  In fact, there are documented instances in the medical literature not only of VBA3Cs, but also of VBA4Cs, and even a VBA5C.  In the lay literature, there are anecdotal accounts of VBA6C as well. 

Chances are very good---more than 3 of 4--that VBA3+C will succeed, and the risk of rupture, although perhaps slightly higher than after 1 cesarean, is still lower than many other possible emergency complications in birth.  VBAC after more than 2 previous cesareans should not be automatically eliminated from consideration, provided the mother is strongly motivated, well informed of the possible risks, and she and her provider know how to maximize her chances of success and minimize the risks.  Many providers DO support VBAC after two OR MORE cesareans as a 'reasonable option' for the most motivated women.  


Comparing the Risks of Repeat Cesarean vs. a Trial of Labor

Considering the possibility of uterine rupture can be very scary, and the emphasis on this rare but potentially catastrophic complication tends to frighten many women out of a trial of labor.  What doctors 'forget' to mention is that elective cesarean doesn't eliminate the possibility of uterine rupture either, and that elective cesareans carry their own set of significant risks to you and to baby as well.  Neither elective repeat cesarean nor a trial of labor are without potential risks.   

Uterine Rupture

Many women don't realize that choosing an elective repeat cesarean does NOT eliminate your chances for uterine rupture.  Doctors often make it sound like rupture only happens during a TOL, and that by choosing an ERCS, you can eliminate even a small chance of a rupture occurring.  Although most studies focus on uterine rupture during TOL, uterine ruptures can and do occur before labor in pregnancy, tend to be more devastating, may result in hysterectomy, and babies have died from it.  It is NOT true that deciding against a VBAC means that you won't have any risk of uterine rupture.  In fact, occasional studies have even found a higher rate of rupture in the ERCS group!  So keep in mind that it is the PREVIOUS CESAREAN that puts you at risk for uterine rupture.  

How does rupture risk compare between the two birth modes? It depends on the study you look at.  In Rosen's 1991 meta-analysis of morbidity and mortality associated with cesareans, a trial of labor was NOT associated with an increased rate of uterine rupture OR fetal death.  However, in Mozurkewich and Hutton's 2000 comparative meta-analysis of data between 1989-1999, a trial of labor was associated with a slightly increased rate of ruptures and therefore fetal death, although the absolute risk still remained small (0.4% rupture, 0.2% fetal death for TOL group; 0.2% rupture and 0.1% fetal death for ERCS group).  

So why did the 1991 study find NO increase in risk for rupture or fetal death with a TOL, yet the 2000 study did? This may reflect the increased rate of uterine rupture some studies have found in the 90s (perhaps due to drug overuse), or it may reflect other factors such as methods used in the analysis.  Although it's unclear at this point, deciding on a trial of labor may increase the risk of rupture slightly overall (especially today with the high rates of induction and drug use), but not by a great deal.  The absolute risk is generally low, and some ruptures and deaths would happen regardless.  ERCS does not prevent ruptures or fetal death completely, as some doctors imply.  And it's not clear whether a TOL really raises the risks of rupture or not, even slightly; some studies seem to support a slight increase in risk, and other studies do not.    

It is not logical to 'forbid' a trial of labor simply because of the vague possibility of uterine rupture.  Women with prior cesareans can rupture at any time during pregnancy, not just in labor. Doctors do not insist that a woman who has had a cesarean spend her entire pregnancy in the hospital just in case she might rupture, or that she forego another pregnancy entirely, simply because she is at increased risk of rupture.  The risk of rupture is real in either group, but statistically small.  Keep the risks in perspective.

Remember also the risk of uterine rupture compared to other complications.  Although some doctors like to use scare tactics, the relative risks of true rupture compare with other uncommon but possible risks of labor.  Dr. Bruce Flamm lists these various risks in his book, Birth After Cesarean: The Medical Facts.  He lists the chances of placental abruption (premature detachment of the placenta) at about 1%, of placenta previa (placenta blocking the birth canal) at 0.5%, of fetal distress in labor at 1-5%, of prolapsed umbilical cord at about 1%.  

According to his figures, average risk of uterine rupture after 1 previous cesarean (<1%) is LESS than risks of other possible complications; the average risk of rupture after 2 or more previous cesareans is apparently only slightly more than any one of these conditions (and about the same as the chances for fetal distress).  If a doctor does not 'forbid' a trial of labor to non-cesarean moms based on fears of placenta previa, placental abruption, cord prolapse, or fetal distress, why should he 'forbid' a trial of labor to prior cesarean moms based on fears of rupture? 

Maternal Risks of Repeat Cesareans

Furthermore, don't forget that elective repeat cesarean operations also carry risks, both to the mother and the baby.  Although modern operative techniques and conditions have made a c/s a much safer operation these days, it still is MAJOR surgery and carries small but very real risks.  And the risks tend to increase with every repeat operation.  Unfortunately, the risks of repeat cesareans are rarely mentioned when doctors discuss the risks and benefits of a trial of labor with a mother, and so-called 'VBAC consent forms' rarely make equal mention of the potential risks of cesareans.  Most often women are advised of the potential risks of VBAC without equal emphasis on the potential risks of cesareans, which are quite real too.

For example, blood loss is about twice as great in cesarean birth, and may increase with each successive operation.  Scarring and adhesions may occur and cause long-term pain, numbness, or other problems; the more cesareans you have, the longer and harder the surgery is because of scarring and possible adhesions.  Some women experience numbness, tingling, burning, or pain near their incision site for years after a c/s. Infection rates are also much higher after a c/s (especially in larger mothers), there can be respiratory problems from anesthesia, decreased bowel function after surgery, or problems with blood clots that can even cause death.  Although very rare, paralysis from spinal/epidural anesthesia can occur as well, and the risk of the mother dying during a cesarean is about 2-4x greater than during vaginal birth.  

The risks of a c/s don't just end in immediate morbidity problems.  In Washington state, women who had cesareans had an 80% increased risk for postpartum rehospitalization within 2 months of the birth (Lydon-Rochelle, 2000). They were at risk for uterine infection, surgical wound complications (30x the risk!), and cardiopulmonary and thromboembolic conditions.  Although the absolute numbers are small, the study found that 1.7% of women who had cesareans had to be rehospitalized for additional problems like these within 2 months.  This takes an enormous toll, both economically and especially personally. It increases the family burden considerably, and is a very difficult disruption of early parenting.  

There is also some evidence that women who have cesareans also have a higher rate of other health problems  such as appendicitis and gall bladder problems (Lydon-Rochelle, 2000).  On the surface, this may seem strange, but people who have abdominal surgeries do tend to experience higher rates of problems like gall bladder troubles, and infection is a risk factor for appendicitis.  Surprisingly, few people thought to associate these problems with cesareans, which shows how lightly our society treats cesarean surgery compared to other surgery.  So although the chances are not high, repeated cesareans may raise your risk for gallbladder disease or other problems.  

Even if your recovery from ERCS is uneventful, it is still more difficult than recovery from normal vaginal birth. Physical recovery generally takes longer, and a number of c/s moms experience significant problems with post-partum depression or even post-traumatic stress disorder. While most women cope okay with c/s recovery, it's not the easiest way to begin parenting, especially if you have older children who also need your attention. VBAC activists point out that if you were adopting a baby instead, you probably wouldn't choose to have major surgery on the day you were to receive custody of the baby.  You could probably manage if the two did coincide, but it's certainly not the most stress-free way to begin.  Cesareans are not just stressful physically and emotionally, but they can also stress early parenting and family life.  In terms of maternal risks, ERCS clearly present substantial potential problems.

Fetal Risks of Repeat Cesareans

ERCS can also present risks to the baby, including a higher rate of breathing problems (Respiratory Distress Syndrome) and problems due to prematurity.   Labor helps prepare the baby to get ready to breathe in the outside world, and babies born by cesarean have a much higher rate of breathing problems and RDS, which can be very serious.  In addition, many OBs schedule ERCS for 38 weeks, and if there is any question on due dates or if the mother's cycles run long, this can cause the baby to be born too soon (iatrogenic prematurity), with the accompanying risks of jaundice, breathing problems, hypoglycemia, difficulty nursing, etc.  Hook (1997) found that 9% of babies born by ERCS were actually younger than the desired 38 weeks, so this is a significant risk.

The baby can also be injured during the cesarean; some babies are cut accidentally during the uterine incision and may have a scar.  Furthermore, babies born by elective c/s sometimes have trouble breastfeeding, their mothers may have delayed initiation of lactation because of the lack of labor hormones to jumpstart lactation, and excessive blood loss during cesarean can cause anemia, an underdiagnosed cause of poor milk supply for many women.  Although cesareans are lifesaving operations in certain cases (which we can be truly thankful for when necessary), cesareans are NOT the way that nature designed babies to be born.  The abrupt transition to life outside the womb without the benefits of labor hormones and the physical process of birth IS a less optimal beginning.  Although this can usually be compensated for, it does have risks.

Risks to Future Pregnancies 

In addition, if you plan future pregnancies, repeat cesareans can really take a toll.   This is a VERY important fact that is rarely mentioned by OBs; the health of your next baby may be impacted by the birth mode you choose this time.  Every time a scar is inflicted upon the uterus, the risk of problems in subsequent pregnancies increases.  For example, Hemminki (1996) found that although the risk was fairly small, women with prior cesareans had "reduced fertility", including more ectopic pregnancies and more miscarriages.  In addition, there was 2-4x the risk for placental abruption (separation of the placenta from the uterus prematurely, which can kill the baby) in women with prior cesarean.  The worst-case scenario of fetal death from uterine rupture is often emphasized when considering VBAC, but placental abruption often is also fatal to babies.  Although both abruptions and ruptures are usually detected in time to save the baby, both have catastrophic potential consequences and must be taken very seriously.  Doctors should not be glossing over abruption risks from repeat cesareans.

The risk for other placental problems following a cesarean are substantial, and increase as the number of cesareans increases.  For example, placenta previa (low-lying placenta that fully or partially blocks the uterus, with strong risk of hemorrhage and possibly death for mother and/or baby) is almost universally acknowledged to be MUCH more common in women with prior cesareans.  Hemminki found a 4-5x risk for placenta previa in women whose first pregnancy ended in cesarean.  And the risk apparently increases with the number of prior cesareans.  Hendricks (1999) found a 2.2x risk for previa after one c/s, a 4.1x risk for previa after two c/s, and a 22.4x risk after 3 c/s.  Ananth (1997) found a 4.5x risk for previa after one c/s, a 7.4x risk after two c/s, a 6.5x risk after three c/s, and a 44.9x risk after four or more c/s.  

Although these are very indicative of a problem, risk ratios can be somewhat misleading in terms of knowing absolute risk.  To compare risks more easily, it's helpful to know what percentage of women with prior cesareans actually get placenta previa, compared to the incidence in the overall population. Ananth (1997) found that the average incidence of placenta previa in the overall population until 1985 was 0.36%, but that after 1985 it increased to 0.48%, a substantial increase when talking about large populations and multiple studies.  They theorize that this increase probably has to do with the increased cesarean rate as well as an increased rate of detection from ultrasounds.  Chattopadhyay (1993) found a previa rate of 0.44% in women without prior cesareans, versus a 2.54% previa rate for those with prior cesareans, a 5-fold increase.  Zaideh (1998) found a previa rate of 0.25% in women without prior cesareans, versus a 1.87% previa rate in women with prior cesareans.  The rate of previa was 1.78% after one c/s, 2.4% after two c/s, and 2.8% after three or more c/s.   So when you consider the rate of uterine rupture after 2 or more cesareans (probably between 1-2% with liberal pitocin use), you also have to consider that having another cesarean would also raise the risks for placenta previa in any future pregnancies (to somewhere around 2-3%), possibly placing your life or your baby's life at risk next time.

In addition, placenta previa is sometimes accompanies by a potentially catastrophic condition called 'placenta accreta' (or percreta).  In this, the placenta actually grows through the uterine wall (and sometimes even into the structures around it, like the bladder) and cannot detach after the birth.  This often results in hysterectomy for the mother, and sometimes even in her death.  In fact, several VBAC studies analyzed for this FAQ noted occasional maternal deaths due to placenta accreta, including the 1993 Chattopadhyay study mentioned above.  Asakura 1995 noted several hysterectomies due to placenta accreta, and found hysterectomy to be 11.3x more likely in women with more than one prior cesarean.  Mozerkewich and Hutton's 2000 meta-analysis found that women in the TOL group had 0.39x the risk for hysterectomy as the women in the ERCS group; this is probably because of the increased rate of accreta found in women with cesarean after cesarean.  Thus, although hysterectomy is a risk for both the TOL and the ERCS group, the risk is probably greater in the ERCS group, probably mostly in the group with multiple cesareans.

Although placenta accreta can occur without prior cesarean, it is much more common with prior cesareans.  For example, Zaideh (1998) found accreta associated with previa in 9% of cases without prior c/s, versus 40.8% of cases with prior c/s.  Similarly, Chattopadhyay (1993) found accreta with previa in only 4.5% of the cases without prior cesareans, versus 38.2% of cases with prior cesareans.  Chattopadhyay further analyzed accreta by the number of prior cesareans; after one c/s, previa was accompanied by accreta in 10% of cases, but after two or more c/s, previa was accompanied by accreta in 59.2% of cases.  And about 2/3 of women who had placenta previa accreta after a c/s required a hysterectomy.  

Risks from a 'Failed' Trial of Labor

To be fair, one complicating factor to a TOL is that there may be a higher rate of infection and other problems if you have a 'failed' TOL.  It's true that the 'failed' TOL group sometimes has more infections or operative injuries etc. than ERCS group.  Some doctors have seized upon potential increased morbidity among the 'failed' TOL group as a reason to discourage women from a TOL (while conveniently forgetting to mention all the risks from ERCS).  Although the 'failed' TOL group may have slightly increased morbidity rates, these are usually minor and not difficult to resolve, and are generally limited to a small percentage of the group.   It's not appropriate to urge surgery simply because a small percentage of women who have a cesarean after a TOL may get infections, some of which may be avoidable by better intrapartum care procedures.

Of course, the worst-case scenario is uterine rupture, and this may be more common in the TOL group than the ERCS group.  However, the question is by how much (studies differ, and not all show a higher risk with TOL), and how many of these ruptures could be avoided by greater caution with induction, avoiding use of multiple labor drugs, and avoiding aggressive early pitocin augmentation.  It may be that with greater caution in labor protocols, the risk between groups might be more equal.  But it's also important to note that while fetal death has occurred with uterine rupture, the majority of cases do not have long-term harm.  Most ruptures of low-transverse scars, if caught and acted upon quickly, do not result in fetal death or injury, and usually do not result in maternal hysterectomy either.  The risk of permanent harm does exist and must be taken seriously, but most cases do end up resolving without significant harm.  (And of course, there can be significant harm from ERCS as well.)  

Keep in mind that women and their babies who do have a VBAC do MUCH better on the whole (less infection, less blood loss, less morbidity) than those having an ERCS, and your chances of VBAC with a decent provider are about 70%.  Because the chances for VBAC are so good, the TOL group (successful or not) tends to have better outcomes statistically than the ERCS group on the whole, as long as the VBAC success rates are high.  If VBAC success rates are lower, then the potential morbidity from the 'failed' TOL group may reduce or completely wipe out the statistical advantages the TOL group usually has.  The moral of this is probably the importance of finding a provider with very high VBAC rates, and beliefs and policies that actively promote VBAC!  In other words, if you are going to choose a TOL, choose only a provider that whole-heartedly supports VBAC, uses policies that minimize potential morbidity, and has a very high rate of VBACs.  If you choose a provider that is more interventive (insists on early induction for VBAC, for example), or has a low rate of VBAC success, your chances for 'failed' TOL and potential associated morbidity increase. 

Potential morbidity in a 'failed' TOL can be probably be minimized by reducing the number of vaginal exams and internal procedures done during labor, perhaps using antibiotic prophylaxis during TOL cesarean if rupture of membranes has occurred previously, and by concentrating on improving wound care.  Instead of promoting surgery to avoid potential morbidity from a 'failed' TOL, providers might do better to emphasize ways to prevent avoidable ruptures, ways to improve outcome should rupture occur, and ways to minimize infections and other 'minor' morbidity that may occur in a small but definite percentage of those whose TOLs end in cesarean. 


While there are some potentially very serious consequences from a TOL, risks are relatively small and usually not catastrophic unless problems are not acted upon quickly.  Similarly, there are also potentially serious consequences from ERCS as well, although these tend to get de-emphasized in VBAC studies and counseling by doctors. Neither TOL nor ERCS completely erase the risk of uterine rupture; the risk is probably slightly higher in a TOL (especially when pitocin etc. is used) but the risk is still reasonable, compares to the risks associated with multiple ERCS, and must be weighed against the better outcomes associated with VBACs.  

The benefits of VBAC are quite significant to both mother and baby, and these factors alone make a TOL sensible for those who desire it.  Statistically, the greatest chance for optimizing outcomes is to be in the TOL group because of the high rate of VBAC success that occurs.  And if you do plan on more pregnancies, a TOL makes more sense since each successive cesarean places you and your future babies at more risk for serious placental problems.  However, as always, the specifics of each case have to be considered separately, and each woman has to consider what's right for her. Statistically, the overall chances for better outcome are with the TOL group, but it's certainly possible that in some cases, ERCS is the more beneficial choice.  Each case has to be decided on an individual basis. 

Finally, as always, it's important to keep all these numbers in perspective.  Chances are very good (about 97-98%) that even if you choose an ERCS, your next pregnancy probably won't have placenta previa.  Similarly, chances are very good (about 98-99%) that if you choose a TOL, you probably won't have a uterine rupture.  But while it's important to remember that neither ERCS nor TOL is totally risk-free, the absolute rate of complications with either an ERCS or a TOL is pretty low, and chances are you won't have significant problems either way you choose.   


Emotional Factors in Considering a VBAC

An Opportunity for Healing

One very important factor to consider when choosing between elective repeat c/s and VBA2C  is psychological influences.  Many women who have had multiple cesareans have special fears or issues around birthing.  Perhaps your own birth was traumatic or difficult, your relatives have had difficult births, you have a traumatic memory of a difficult first labor, you do not trust your body to 'work right', have a history of infertility, or a sexually transmitted disease.  Although these potential psychological issues do not have to be totally resolved before you can have a VBAC, most of the time it does help to do some work towards acknowledging and starting to heal them in order to work towards a VBAC.  

There are many reasons why the mind or emotions can affect the decision-making process or even the physical progress of labor.  These need to be carefully examined, acknowledged, and worked on for the sake of general emotional healing and in order to increase your chances of a VBAC.  These may include:

In their excellent book, Natural Childbirth After Cesarean, Karis Crawford and Johanne Walters list 20 questions that help women discover underlying attitudes that may affect their birthing and VBAC chances.  Here are a few:

Many women with multiple cesareans who are considering VBAC benefit from counseling during pregnancy, either from therapists, childbirth educators, hypnotherapists, or therapists/educators that specialize in birth-related counseling.  If you plan to consider VBAC, you may want to strongly consider doing journaling exercises, reading books specially designed for addressing birthing issues, joining a support group of other women considering VBACS to have continuing dialogue with sympathetic peers, additional childbirth education classes (Birth Works in particular), and often additional counseling/therapy (hypnotherapy can be useful).   Relaxation training, yoga, visualizations, affirmations, hypnotic suggestion, exploration of feelings and dreams through artwork and journaling, etc. can all be helpful in exploring the psychological baggage we all bring to our births, and to work on healing and optimizing our lives, regardless of whether we have a VBAC or not. 

Resources for working on emotional issues surrounding birth include:

Another good resource is Creating A Joyful Birth Experience by Lucia Capacchione and Sandra Bardsley, which deals with many of the same issues but in a birthing context.  Although not easy to find, or, still have this wonderful book.  Another book useful for dealing with how emotional issues can affect your health is Peace, Love and Healing by Bernie S. Siegel, M.D.  It does not deal directly with birthing issues, but does contain many useful ideas for getting in touch with what your body is trying to tell you.  

There are so many things you can do to work on emotional housecleaning or spiritual cleansing before your next baby arrives.  Some of these ideas undoubtedly sound a little 'out there' or 'granola-crunchy' to some women (they did to Kmom!), but many women have found them to be helpful in working towards a better birth.  Find the ones that appeal to you and pursue them.  Don't approach birth only from intellectual learning; emotional learning is just as powerful, but in different ways.  Approach your birth from a multifaceted perspective.


Healing Choices After a Previous 'Failed' Trial of Labor

Although on average, almost 3/4 of the women who attempt VBAC after 1 previous c/s succeed, on average 1/4 of them do not.  If you, like Kmom, are one of those 1/4 with a 'failed' trial of labor, it can be very difficult to decide what to do in a subsequent pregnancy.  Should you skip straight to an elective repeat c/s, or should you attempt a VBAC again?  No one can answer this question for you, and there is no one 'right' answer.  For some women, it is emotionally 'right' to elect a repeat cesarean, and for others, it is emotionally 'right' to go for another VBAC.  Each woman must look carefully within herself and discover the answer that is right for her. 

Statistically as a group, a trial of labor for a vaginal birth is still generally as safe or safer than an elective repeat c/s, as long as there is a high rate of VBAC success in the group.  Although there is not a great deal of data on women who elect another trial of labor after a previous 'failed' trial of labor c/s, there are a number of anecdotal stories of women who do have a VBAC the second or even third time around.  According to Phelan 1989, you have at least as good a chance of having a vaginal birth this time as you do ending up with another c/s, even after 2 prior cesareans for 'CPD".  And with many providers the chances are probably much better than even.  Although the risk of complications with a c/s after a 'failed' TOL may be slightly increased, studies do show that maternal and fetal outcome are better after VBAC overall, so given the even or better odds for a vaginal birth this time on average, it is statistically to your benefit to try for a VBAC.  

If so, why do some women choose elective repeat cesareans? For some women, it is emotionally safer to elect a repeat c/s and forego the possibility of another disappointment.  It is not easy to commit to the work of VBAC and then end up with another c/s (Kmom knows!).  The uncertainty of not knowing the outcome in a trial of labor is very difficult for many women; sometimes the certainty of a known quantity (the c/s) is more comforting. Other women choose elective repeat c/s because they are unwilling to risk even a slightly increased chance of uterine rupture from a trial of labor (even though choosing an elective c/s does not eliminate the risk of rupture completely).  Still other women have difficulty finding a provider who would be willing to 'allow' a trial of labor after a previous trial of labor failed, or find it difficult to contemplate going through another difficult labor if they were previously induced (very understandable!).  And some women have a medical consideration that may make a repeat cesarean a more logical choice.  Again, for some women, an elective repeat c/s can be the right choice, and it is not the intention of this FAQ to criticize that choice.

For some women, however, it CAN be the right choice to pursue another VBAC, even after having had a 'failed' trial of labor.  They may feel that a change of provider will increase their chances of success, they may resolve emotional or physical issues that may have impacted past labors, they know that a trial of labor is still a reasonable choice statistically than a repeat cesarean, or they feel that they never had a truly fair shot at a vaginal birth previously.  Other women choose a trial of labor, reasoning that even if they end up with a repeat c/s, the labor prepares the baby and mother for birth more efficiently prior to the c/s.  The babies tend to have less breathing difficulties at birth, breastfeeding may be easier, and surgery tends to be easier after labor thins out the lower uterine segment.  To these women, these benefits outweigh the possible increased risk of rupture or infection, and they see their labor as benefiting the baby greatly, whether it ends in repeat c/s or in vaginal birth.

However, it's important to point out that any woman who chooses to pursue a VBAC must be emotionally prepared for a repeat cesarean.  This is NOT a 'pass or fail' issue; it is not a measure of doom or a show of a lack of confidence in VBAC to emotionally prepare for this possibility.  In some cases (such as complete placenta previa, a transverse baby whose position will not resolve, an abrupted placenta, etc.) a repeat cesarean is the safer choice.  In other cases, a repeat c/s may become the option of choice if labor does not progress despite all appropriate measures for comfort and help.  Chances are that you will have a VBAC, but if you do have a repeat cesarean, it is not a 'failure'.   

The point is NOT that you must be prepared to 'fail'; the point is that a mother needs to get to a place emotionally where she CAN consider the possibility of a repeat cesarean without feeling like a failure.  In fact, oftentimes women find that once they can accept this and find a way to make it into a decent birth anyhow, they are often able to release their anxiety better and concentrate more fully on a VBAC.  

It should be emphasized that it is important to concentrate your time and energy on thoughts of vaginal birth and that the chances for success after 2 previous cesareans are really quite good, but that a small compartment of you should be emotionally prepared in case of an unexpected development that necessitates a c/s.  Oftentimes, the best choice is to aim for spiritual growth and healing and a better birth this time instead of focusing on the method of delivery as the measure of 'success' or 'failure'.  

Kmom's Story: Kmom chose to go for a VBAC again even after 2 diagnoses of 'CPD', even after dilating completely and pushing for hours both times, one a 'failed' VBAC attempt.  Most doctors would not have given her much chance of future success given this history, her age, her weight, her past history of gd, etc. The decision to go for a VBAC again was not easy, and was taken only after a great deal of soul-searching and research.   In Kmom's opinion (and the opinion of her midwives), the risk of rupture or other problems was outweighed by the risk of hemorrhage, anesthesia risks, infection, future placental problems, and neonatal breathing difficulties presented by elective repeat c/s.  Physically, Kmom felt that the technical cause of her previous 2 c/s was fetal malposition, not true CPD, and that this was never adequately even addressed.  With a truly knowledgeable attendant, techniques, and special awareness from Kmom, these malpositions might well be avoided the next time.  Emotionally, pursuing a VBAC seemed to be the right choice of action for her, one that resulted in the most spiritual and emotional growth, regardless of the actual birth outcome.  

Kmom's first pregnancy was highly medicalized and ended with a difficult induction.  Despite everything, she did dilate fully and pushed for 2 hours, but still ended up with a c/s, probably because the baby was malpositioned.  The c/s was a true *horror* because the anesthesia did not fully take and she felt the surgery intensely.  This was deeply, deeply traumatic.  

In her second pregnancy therefore, she was highly motivated to try for a VBAC. (!)  She labored naturally and spontaneously, dilated completely, and pushed for nearly 5 hours, but the baby was posterior (sunny side up) and got 'stuck', so she ended up with another c/s.  Fortunately, this time she had 'spinal' anesthesia which worked very well, and the second c/s was a 'good' one. Although not achieving the much-desired VBAC in her second pregnancy was difficult and disappointing, with hindsight Kmom believes that the VBAC attempt  was still the best possible choice for her.  She took much more careful care of herself and her baby as a result, found the empowerment to research birth issues such as gestational diabetes in order to better make her own choices (and actually prevented the gd from recurring), found the guts to switch providers when needed, and had the wonderful gift of a terrific natural labor (MUCH easier than a pitocin labor!).  By having a second c/s that was 'safe' and comparatively 'good', she was also able to resolve some of the trauma and horror of her first c/s, and the recovery was much easier physically and emotionally.  

With more hindsight, she can see that much of her second pregnancy and labor was constricted by the fears she brought from the first pregnancy and birth, general attitudes of body mistrust, unresolved abuse issues from the past, and hesitancy in questioning the medical authorities.  Although she made some progress towards working on these issues in the second pregnancy, there simply wasn't the time or available resources to process these enough for the second birth.  It was her hope that the tremendous amount of work she put into these issues in her third pregnancy would assist in an even better birth experience, be it by VBAC or repeat cesarean after trial of labor, although of course she preferred the idea of a VBAC!  

However, Kmom was certainly tempted by the idea of elective repeat c/s, especially the certainty of knowing the outcome ahead of time.  She found the uncertainty to be the hardest part of choosing another trial of labor, but felt that the emotional growth opportunities were greater for her in a trial of labor than choosing the emotionally 'safe' route.  However, she had to work hard to see this as a quest for a better birth and emotional learning opportunity rather than a 'pass/fail' test, and to be accepting of the outcome, whatever it was.  

In the end, Kmom did have a VBA2C (and a very joyful one at that!), although it was not an easy birth.  Although she prevented the posterior position from recurring, there was still a minor position problem that caused dilation difficulties and much pain.  However, this time she was eventually able to resolve the position (probably a 'nuchal arm') and the baby was born very quickly after that (only 12 minutes of pushing this time!).  Despite the physical pain of another malposition (a more minor malposition this time, but not minor pain!) and the emotional rollercoaster of the labor, Kmom was glad to have chosen another TOL, and thrilled to have her baby normally.  And the recovery was certainly much easier after a VBAC than after a c/s!

Though she would have been quite disappointed indeed to have had another c/s, she was glad she chose another TOL.  She would not have traded the spiritual growth she found on this journey, not even for the emotional certainty of choosing a repeat c/s.  For her, choosing to pursue a VBAC was worth it, even had she not ended up with a VBAC.  However, because the journey was not an easy one, it reemphasized her empathy and understanding for women who do not choose a trial of labor again.  For Kmom, a trial of labor was absolutely the right choice and she is glad she pursued it, but each woman must follow her own inner wisdom.  

For many women, choosing the VBAC path is its own reward and is perfectly sane, even after having had one (or more!) previous c/s after a full trial of labor.  Others may choose differently. The only 'failure' here is the failure to follow your own inner intuition.  

One last heartening note is that women who have had a 'failed' trial of labor often do go on to a VBAC in subsequent pregnancies.  Gayle Peterson, PhD., and Dr. Lewis Mehl, in the pioneering book series on Pregnancy As Healing, note that: 

"For some women the experience of repeat cesarean following VBAC preparation can be a valuable release of control...In our clinical experience, there is a tendency for women who do have repeat cesareans to give birth vaginally within two to three years following the initial VBAC work, usually in a third pregnancy.  Birth is always progressive.  Regardless of outcome, birth leads to further awareness within a holistic understanding of the process.  The phenomenon of subsequent pregnancy and vaginal delivery following previous VBAC preparation and cesarean cannot be overlooked in our continual understanding of birth as life process and not end goal!"  [emphasis theirs]

If you have had a 'failed' trial of labor, it doesn't mean that you will 'fail' again; at least one study plus plenty of anecdotal evidence shows that you still have a good chance at a VBAC.  Nor does it mean that the trial of labor was even a 'failure'.  It has to be viewed as just one point in the continuum of healing in your life, whether you subsequently choose an elective repeat cesarean section or another VBAC attempt.  Look for the lessons to be learned, find and address your own personal growth issues, and THEN make the decision of what kind of birth to aim for in your next pregnancy.  

Open your heart and listen to your baby in making your decision, do as much as you can to be as healthy as possible, and then find a way to LET GO and follow whatever path occurs.  Expect nervousness, doubt, and setbacks along the way, but keep your eyes on the goal---the best possible birth under whatever circumstances arise, and growth along the healing continuum!  


Increasing the Odds for a Safe and Successful VBA2+C

It is reassuring to know that even as imperfect and inconsistent as some of VBA2C research is, it still shows that if you choose a TOL, statistically you are likely to have a VBA2C, and that harm is not very likely as a result of trying.  However, there are never any guarantees in life or birth, and each woman must weigh the risks and benefits of each choice before deciding which is the best course for her and her baby.  There ARE real risks to consider, both with an ERCS and a TOL, and women must decide what is best for them both physically and emotionally.  It is not an easy choice for many women to make.

If you do decide to go for a VBAC, there are some things to consider that may help you in your journey towards a better birth (and hopefully a safe and wonderful VBAC).  Of course, it's important to remember that there are no hard and fast 'rules', and obviously none of this is medical advice.  Due to circumstances specific to your case, you may need to do things differently.  But it may be helpful to spend some significant time reflecting on the following ideas.

Increasing the Odds for VBAC

Here are some ideas to consider that may help you increase your odds of a successful VBAC.

Medical Considerations

Medically, there are a number of things to consider that may help you towards a VBAC or to minimize the risk of rupture.  Again, none of these are medical advice, and of course your situation may dictate a different approach.  Consult your provider for advice on your specific situation.

Emotional Homework

Finally, as previously noted, emotional homework is often an extremely important component to preparing for a VBAC, and probably particularly so for a VBA2+C.  Many women find that pregnancy is a wonderfully rich opportunity for working on life issues, grieving old hurts, and resolving  fears.   Think of this as a powerful opportunity for healing, regardless of mode of birth.  Here are some ideas that may help you 'shake your soul and let the glory come out'.  


There are many things you can do to proactively work towards a better birth. It may help to take a multi-disciplinary approach to preparing for a VBAC so you can approach it from several different angles.  

First, you need to consider what courses of action may increase your odds for a VBAC, and what you can do to surround yourself with people supportive of your goals.  Second,  you need to research birthing and medical issues so that you can make well-informed choices, and so that you can discover ways to minimize risk whenever possible.  Third, you need to prepare yourself emotionally, to take advantage of the opportunity for emotional healing of the past, and to concentrate on approaching the next birth in a positive and loving way.  

No one can guarantee a VBAC, but most women find that when they work very proactively on many fronts, they grow along the healing continuum regardless of how their baby ends up being born.  Work for a better birth, look for the lessons to be learned, then release control, LET GO and let your birth unfold as it will!  

Wonderful birthing wishes to you all---------Kmom 



VBA2C Studies 

*Lists only studies after about 1979 because prior studies do not permit legitimate comparison with modern conditions and methods.  Studies are listed in chronological order. [If you know of any additional VBA2+C studies not analyzed here, please email Kmom ( with the specific reference, and the abstract if possible.] 

**Remember that 'dehiscence' means an incomplete or symptomless scar separation, thinning, or window (clinical significance questionable). 'Rupture' means a complete opening of the scar with symptoms like bleeding, fetal heart rate problems, etc. and potentially serious complications.  

Saldana, LR et al.  Management of Pregnancy After Cesarean Section.  American Journal of Obstetrics and Gynecology.  November 1979.  135(5):555-61.  

Early VBAC study (with relatively modern conditions) which did have VBAC after multiple previous cesareans.  There were 38 trials of labor in the 2+ c/s group, and 22 (or 58%) ended up with VBA2+Cs.  Among these were 4 VBA3Cs.  Although the 'success' rate of 58% is not very high, it is much higher than the 39% VBAC rate in patients with 1 or more c/s!  Authors put enormous limits on the TOL, which explains why the success rates were so low.  There were no dehiscences or ruptures in either TOL group; the only dehiscence occurred in the ERCS group with one previous cesarean.  

Wadhawan, S and Narone, JN.  Outcome of Labor Following Previous Cesarean Section. International Journal of Gynaecology and Obstetrics.  February 1983.  21(1):7-10.

Small study from 1979-80 in Zambia.  There were 319 TOLs, and a 63% VBAC rate.  Only 4% were induced and only 2% had augmentation--a far cry from our rates in the US!   There were also 4 VBAC breeches, and 2 VBAC breech births of a second twin.  Of the women who had a TOL, 31 had had 2 prior cesareans.  22/31 ended up with a VBAC (a 71% VBA2C rate).  There were no ruptures in either group, although 2 women in the VBA2C group (and 3 in the VBA1C group) were rushed to surgery with signs of 'impending ruptures'.  Since the study states there were no ruptures, either these were caught before they ruptured, or as often happens, they overreacted and there really wasn't any impending ruptures occurring.  It's impossible to say, so the rupture data from this study wasn't counted in the FAQ totals..

Martin, JN Jr et al.  Vaginal Delivery Following Previous Cesarean Birth.  American Journal of Obstetrics and Gynecology.  June 1, 1983.  146(3):255-63.  

Studied 162 women who had a TOL, and found an overall rate of 62% VBAC.  0.6% had a rupture (and had been given pitocin).  Of the TOLs, 19 were in women with 2 or more c/s.  Of these, 12/19 had a VBA2+C (63%).  Of the 19, 13 had had 2 previous cesareans (9/13 or 69% had a VBAC), and 6 had had >2 previous cesareans (3/6 or 50% had a VBA3+C).  There were no ruptures in any of the multiple cesarean women who had trials of labor.  

Porreco, RP and Meier, PR.  Trial of Labor in Patients with Multiple Previous Cesarean Sections.  Journal of Reproductive Medicine.  November 1983.  28(11):770-2.

Another early VBAC study.  21 patients with 2+ previous cesareans had a TOL; 17/21 or 81% had a VBA2C (this compares to a 85% VBA1C rate there).  There were no ruptures or dehiscences of scars.  Of special note, 7 of 9 women (78%) who had had previous cesareans for CPD/FTP had a VBAC.

Tahilramaney, MP et al. Previous Cesarean Section and Trial of Labor: Factors Related to Uterine Dehiscence.  Journal or Reproductive Medicine.  January 1984.  29(1):17-21.

This study has a lot of problems and so was not used in many of the analyses.  Many of the numbers do not add up correctly, it doesn't distinguish well between dehiscence and rupture, and VBAC rates etc. specifically for the multiple c/s group cannot be determined.  The study retrospectively examined 836 patients with at least one previous cesarean, 308 of whom had a trial of labor.  78% had a VBA1+C.  At least 185 women had had multiple previous cesareans, but how many had a TOL (or their VBAC rate) is unknown. This study did show an increased rate of dehiscences with an increasing number of uterine incisions, but the difference did not reach statistical significance, nor was it clear how many were in the TOL group vs. the ERCS group.  There was a rate of 2.6% after 1 c/s, 3.0% after 2 c/s, and 7.5% after 3 cesareans.  However, again, these did not reach statistical significance, nor did it appear that these dehiscences were clinically relevant (i.e. true ruptures) although more information is needed to know for sure.  Distinctions between dehiscences and ruptures were not clearly made at all; the summary reads as though there were 5 ruptures out of 836 total patients in the study; most of these appear to be in the elective repeat cesarean arm of the study and if they appeared in any of the multiple c/s patients, it was not specified. So the exact status of rupture rates in multiple cesarean mothers cannot be determined, but the authors do conclude at the end that "the number of previous C/Ss...appear to have little, if any, prognostic significance for uterine rupture."  They also found that infant birth weight had little statistical significance on rupture rates as well.

Farmakides, G et al.  Vaginal Birth After Two or More Previous Cesarean Sections.  American Journal of Obstetrics and Gynecology.  March 1987.  156(3):565-6.

Studied 57 women with 2 or more previous cesareans who had a TOL, and compared them to 64 women with 2 or more previous cesareans who had an ERCS.  44 women had a VBAC, for a VBAC rate of 77%.  Study notes that 18 women with 3 previous cesareans received a TOL, but does not note their success rate.  One woman who had a VBAC was noted to have a dehiscence, but it was 'silent', meaning there were no observable problems with it.  There were no ruptures in this study.    

Stovall, TG et al.  Trial of Labor in Previous Cesarean Section Patients, Excluding Classical Cesarean Sections.  Obstetrics and Gynecology.  November 1987.  70(5):713-7.

272 women with 1 or more previous cesareans underwent a TOL.  Overall, 77% had a VBAC.  In the group with only 1 prior cesarean, 75% had a VBAC, and there was one rupture (0.4%).  In the group with multiple previous cesareans, 39 women with 2 previous low transverse cesareans had a TOL, and 80% had a VBA2C.  6 women with 3 previous low transverse cesareans had a TOL, and all 6 had VBA3Cs (100% success).  There were 5 women with 2 prior low vertical c/s, and 1 woman with 3 prior low vertical c/s.  All 6 had a VBAC (100% success).  There were NO ruptures in the either the multiple previous transverse or vertical incision groups.  Other interesting points are that the VBAC rate was 85% without oxytocin, 74% with oxytocin.  Similarly, the VBAC rate was 86% without an epidural, and 75% with an epidural.  77% of those whose previous cesarean(s) had been for 'dystocia' had a VBAC, and 37% of women with previous c/s for CPD subsequently had larger babies vaginally.  The authors conclude, "The results of this study suggest that a trial of labor is a safe alternative for patients with a previous single or multiple lower uterine transverse incision or a lower uterine vertical incision."  

Phelan, JP et al.  Vaginal Birth After Cesarean.  American Journal of Obstetrics and Gynecology.  December 1987.  157(6):1510-5.

VBAC study of 1796 women over a 2-year period in Los Angeles.  Overall, there was an 81% VBAC rate.  In the second of the two study years, women with multiple previous cesareans were also 'allowed' a TOL, and results were specified by the number of previous cesareans.  82% of women with only 1 previous cesarean had a VBAC, 72% of women (n=149) with 2 previous cesareans had a VBAC, and 90% of women (n=10) with 3 previous cesareans had a VBAC.  When the results of both VBA2C and VBA3C are figured together, the overall success rate for VBA2+C was 73%.  Other important points include that 77% of women with previous cesareans for CPD had a VBAC, and the rupture rate between TOL and ERCS groups was similar.  The rupture rate was NOT increased in women with multiple previous cesareans in this study.  Interestingly, the VBAC rate with use of oxytocin was 70%, while the VBAC rate without the use of oxytocin was 91%.  Although the rate of dehiscence was slightly higher in the group with oxytocin/pit, the difference was not significant.  The oxytocin in this study was almost exclusively for augmentation, not induction. Therefore the risk of pitocin induction is not addressed here.  The authors conclude at the end that, "In patients with two prior cesarean sections, a trial of labor appears to be a reasonable alternative."

Flamm, BL et al.  Vaginal Birth After Cesarean Section: Results of a Multicenter Study.  American Journal of Obstetrics and Gynecology.  May 1988. 158(5):1079-84.

Studied 1776 women who had a TOL after one or more prior cesareans.  Of the entire group, 74% had a VBAC overall, with 0.6% having a dehiscence and 0.2% experiencing a true rupture (all in the VBA1C group).  78% of those who did not receive pitocin having a VBAC compared with 64% of those who did receive pitocin. There were 89 women who had a TOL after 2 or 3 prior cesareans; 76% of these women had a VBA2+C.  The VBAC rate was similar among women with 1 prior c/s (74%), 2 prior c/s (77%), and 3 prior c/s (71%).  There were NO ruptures in any of the women with multiple prior cesareans, 1/4 of whom received pitocin and only 3% of whom had epidurals. Notes that the available data as of 1988 showed no major increased risk of rupture during TOL after multiple cesareans, but noted the need for more data.  Also scolds hospitals that were balking at having TOLs because they 'might not be prepared'; notes that the risk of maternal hemorrhage from an abrupted placenta or placenta previa was greater than the risk of uterine rupture, and that acute fetal distress, cord prolapse, and postpartum hemorrhage were all more common than rupture from a low-transverse cesarean as well.   

Pruett, KM et al.  Is Vaginal Birth After Two or More Cesarean Sections Safe?  Obstetrics and Gynecology.  August 1988.  72(2):163-5.  

55 women had a trial of labor after 2 or more c/s; the VBAC success rate was particularly low at 45% after 2 c/s (50% after 3 c/s, very small sample size).  There was a 5.5% scar dehiscence rate, all of whom had been given pitocin (2 of the 3 were also grand multips, who are also more prone to rupture).  Descriptions given make 'dehiscence' vs. 'rupture' unclear, but the authors state outright that there were no ruptures in the study, so this was the figure used for the analyses.  Population was mostly indigent, had mostly unknown scars, and 2 low vertical scars were also included in the study.  55% of the women received pitocin augmentation; these women had a 30% VBAC rate compared to a 64% VBAC rate in the no pitocin group.  In addition, all of the women with scar dehiscences were in the group that had received pitocin as well.  There were 0 ruptures and 0 dehiscences in the VBAC group that received no pitocin.

Phelan, JP et al.  Twice A Cesarean, Always a Cesarean?  Obstetrics and Gynecology.  February 1989.  73(2):161-5.  

501 women with 2 or more previous cesareans had a TOL, and 69% had a VBAC overall.  [It is possible that this study includes some of the same subjects that were included in the Phelan 1987 study, but there is no way to know for sure.  Therefore, each study has been counted as separate.  If there were duplicates, the FAQ's analysis may be slightly off, but probably not by a great deal.]

There was a 1.8% incidence of scar dehiscences in the TOL group (vs. a 4.6% rate in the ERCS group), and there were NO true ruptures in the TOL group (vs. 0.2% rate in the ERCS group).  Women who had had at least one previous cesarean for CPD/FTP had a 64% VBAC rate.  Those who had had 2 previous labors ending in c/s (as opposed to repeat elective cesareans) had a VBAC rate of 53%.   Those who had had 2 successive labors both ending in c/s for CPD/FTP still had a 56% VBAC. In other words, even those women with a previous 'failed' trial of labor still had a better chance of a VBAC than another 'failed' TOL. Pitocin use in this study was very high, with 57% of women receiving pitocin.  Most, however, received pitocin for augmentation (94%) instead of induction (6%).  Pitocin use decreased VBAC success rates (58% with pitocin vs. 83% without pitocin) and increased dehiscence rates (2.1% with pitocin vs. 1.4% without pitocin).  VBA2C TOL patients who received pitocin had a 2.5x risk for c/s, 1.5x risk for dehiscence, and 3.5x risk for febrile morbidity (fever needing treatment).  

On a different note, a previous vaginal delivery did increase the chances for VBAC; 81% of women with a previous vaginal delivery had a VBAC vs. 67% VBACs in women who had never had a previous vaginal birth before.  (However, the odds were still 2 of 3 that women without a previous vaginal birth would still have a VBAC!)  In this study, "The incidence of scar dehiscence [did] not appear to be affected by the number of previous uterine incisions, nor by a trial of labor."  The authors conclude that, "Trial of labor in patients with two previous cesareans appears to be a reasonable consideration." 

Novas, J et al.  Obstetric Outcome of Patients with More Than One Previous Cesarean Section.  American Journal of Obstetrics and Gynecology. February 1989.  160(2):364-7.

36 women with 2 or more previous cesareans had a TOL; overall, 80% had a VBA2+C.  21/27 with 2 previous cesareans had a VBAC (78%); 8/9 of women with 3 or more previous cesareans had a VBAC (89%).  (The VBA1C rate in the same institution was much lower.) Included in the study were those with low vertical scars, those in labor with prior classical scars, those with previous uterine fibroid surgery, and those with unknown scars.  Almost half the patients had their labor induced with pitocin.  The only uterine rupture occurred in a woman with two previous classical scars who was also receiving pitocin augmentation.  There were no ruptures in women with multiple low transverse scars.  Of 15 patients with a prior cesarean for 'dystocia' (CPD/FTP), 14 had a VBAC (93%), and 3 gave birth to larger infants vaginally than with their previous cesarean.  

Veridiano, NP.  Vaginal Delivery After Cesarean Section.  International Journal of Gynaecology and Obstetrics.  August 1989.  29(4):307-11.  

194 women with previous c/s had a TOL; 78% delivered vaginally and there were 2 ruptures for a rupture rate of about 1%.  24 or 25 of the women offered a TOL had multiple scars (the study has several typos and minor errors in its report, so sometimes the numbers were off a little).  Does not specify the VBAC rate or rupture info for women with multiple scars, although they do note that 14 women with 2 previous c/s, 4 women with 3 previous c/s, 2 women with 4 previous c/s, and 1 woman with 5 previous c/s did have VBACs.  This adds up to 21 VBACs out of 24 or 25, resulting in a VBA2+C rate of at least 84%.  No individual VBAC rates for each number of previous cesareans was given.  They end by saying, "We conclude that women with multiple previous CS scars can safely deliver vaginally as can women with unknown uterine scars, with careful intrapartum surveillance."  They also 'allow' VBAC women with breech or multiple gestations to labor and deliver vaginally.  

Wessel, J et al.  Deliveries in Patients with More Than 1 Cesarean Section.  Z. Geburtshilfe Perinatol.  May-June 1990.  194(3):126-30.  [from abstract]

16 women had a TOL after 2 or more previous c-sections.  12/16 or 75% had a VBA2+C.  The authors state, "The justifications for a repeated primary cesarean section based on the previous record to two or more cesarean sections alone seems to be no longer given."  

Hansell, RS et al.  Vaginal Birth After Two or More Cesarean Sections: A Five-Year Experience.  Birth.  September 1990.  17(3):146-50.  Discussion 150-151.

35 women with 2 or more previous c/s had a trial of labor; overall 77% had a VBAC.  Of the women in the study, 5 had had 3 previous cesareans, and 3 of the 5 did indeed have a VBA3C, for a VBAC rate of 60%.  1 woman in the study had had 4 previous cesareans, and she also went on to have a VBA4C (100% vbac rate).  If you consider the two groups together, the success rate for women with 3 or more cesareans was 67%.   There were NO ruptures in women who had a TOL, but there was a rupture in the ERCS group.  Of the women whose first cesarean was for CPD, VBAC rates were lowered, but even so, 50% still had a VBAC, and 3 of 7 (43%) had a vaginal delivery with babies who were larger than the "CPD" c/s infant. Also, there was one twin VBAC after 2 or more cesareans.  In this study, the rate of morbidity between women who had had repeat cesareans after a failed TOL was similar to the rate of morbidity in women who had ERCS. 

Flamm, BL et al.  Vaginal Birth After Cesarean Delivery: Results of a 5-Year Multicenter Collaborative Study.  Obstetrics and Gynecology.  November 1990.  76(5 Pt 1):750-754.

5 year multicenter study of VBACs in 11 hospitals.  There were 5733 TOLs and 4291 VBACs, for an overall VBAC rate of 75%; the rupture rate was 10/5733, or 0.2%.  The rate of VBACs without pitocin was 78%, versus 68% when pitocin was used (6/10 ruptures had had pitocin, but the increase was not statistically significant).  The overall VBAC rate after a c/s for CPD/FTP was 65%, for breech 89%, for fetal distress 73%, and 'other' was 77%.  

There were 168/245 VBA2+Cs in this 5 year trial, but 89 of these had already been reported in Flamm's 1988 study (see above).  Therefore, only the 156 TOLs in the last 3 years of the study were counted for the totals in this review FAQ (so as not to count the same VBA2Cs twice).  100/156 women with 2+ previous cesareans had VBA2+Cs in this second part of the study, for a 64% VBA2+C rate to add to the totals here.

The authors do not specify how many ruptures were in this group, although one rupture case (including a fetal death) was listed as occurring in a woman with 2 previous cesareans.  Her skin incision was vertical; they were unable to determine what type of uterine incisions she had had, and she labored at home till full dilation (apparently with no monitoring, for the baby's heart rate was very low at admission and rupture had already occurred).  This may well be a rupture case in a woman with 2 previous classical incisions (which have a higher rupture rate), but it is impossible to establish this for sure. The authors do state that even with this statistic, "The incidence of uterine rupture...did not differ significantly from that in the group of patients with one previous cesarean." 

Roberts, LJ.  Elective Section After Two Sections-Where's the Evidence? (Review)  British Journal of Obstetrics and Gynecology.  1991.  98(12):1199-1202.  

"There is no conclusive proof of an increased risk of scar dehiscence during labor after two cesarean sections and the manner in which we have come to believe that there is should be an embarrassment to all who consider obstetrics to be a scientific specialty."  Says that studies have found no increased risk in 2 previous c/s and high VBAC success rates, even when one of the cesareans was for CPD. [Note that the 'no increased rupture rate' was true in the studies on VBA2C in the 80s, but that the overall rupture rate rose in the 90s, and several 90s studies did find a higher rupture rate after multiple cesareans.  The question is why this did not show up before, why the rupture rate increased in the 90s, and which decade of research represents the 'true' rate of rupture for VBA2C, or if the answer lies somewhere in between.}

Leung, AS et al.  Risk Factors Associated with Uterine Rupture During Trial of Labor After Cesarean Delivery: A Case-Control Study.  American Journal of Obstetrics and Gynecology.  1993.  168:1358-63.  

Studied various factors to see if they were associated with uterine rupture in a TOL.  70 patients over a 7 year period who had had a uterine rupture during a TOL were studied.  The risk of uterine rupture was increased in those who had an 'excessive' amount of pitocin, who had experienced 'dysfunctional' labor, and who had a history of 2 or more cesareans.  (Epidurals, macrosomia, history of VBAC, unknown scar, and history of CPD c/s were not associated with rupture. History of prior VBAC, on the other hand, did not decrease the risk of rupture.)  Authors note that 77% of women with uterine ruptures had had pitocin.  They noted that women without previous cesareans who came in in early labor were usually discharged home to wait for active labor, but that women with prior cesareans were not permitted to go home once they had had some contractions.  Because the residents caring for them were so busy, the authors admit that many women in the early stages were given pitocin (instead of therapeutic rest)  if labor did not progress quickly, many even before 'dysfunctional labor' patterns.  In fact, about 90% of the women who ruptured were admitted in early labor, dilated to 4 cm or less; 69% of women with ruptures had had pitocin started at 3 cm dilation or less.  This "forcing" of labor in the latent phase may well be a very strong factor in these uterine ruptures. Use of pitocin was associated with a 2.4x risk of rupture; 'dysfunctional' labor was associated with a 8.1x risk of rupture. 

The rupture rate in women who had had 2+ cesareans was about 2% (vs. 0.82% in the overall VBAC TOL group).  [It would be interesting to see how many of the VBA2+C ruptures had had pitocin augmentation in the latent phase of labor!] This made the rupture risk rate about 2.6x that of women with only 1 cesarean; after adjusting for possible confounding variables, the risk rate increased to 3.8x.  However, the authors are careful to point out that "98% of the patients with two or three prior cesarean deliveries underwent trial of labor uneventfully."  The only recommendation the authors make is careful observation for progression of labor, since 'arrest disorders' tended to increase the risk of rupture.  They advocate that if labor stalls, even after pitocin augmentation, providers should proceed to a c/s without undue delay.

Some critics will use this study to advocate against VBA2+C, and the increased rate of rupture IS a concern (although note that 98% of VBA2+C TOLs had no problems!).  But perhaps the lesson to be learned here instead is that labor should not be forced.  An alternative interpretation might be to not go to the hospital too early (so as not to be so subject to quick pitocin augmentation), to try other ideas if labor does not progress well in the early latent stages before forcing the issue with pitocin, to be very cautious when pitocin is used, and to carefully watch baby's progress if labor stalls for a significant period of time, especially when pitocin is also used.   It is probably true that if labor stalls for a long time even with pitocin, rupture risks may well increase.  However, an alternative course might be to check for a baby malposition (i.e. posterior babies or asynclitic babies often cause labor to 'stall'), emotional dystocia, or other possibilities before resorting to pitocin so quickly.

Granovsky-Grisaru, S et al.  The Management of Labor in Women with More Than One Uterine Scar: Is a Repeat Cesarean Section Really the Only "Safe" Option?  Journal of Perinatal Medicine.  1994.  22(1):13-17. 

Israeli study investigating VBA2C.  26 women with two or more prior cesareans had a TOL, and were compared with a similar group had a ERCS.  73% of the TOL group had a VBAC.  There were no ruptures or perinatal losses.  80% had an epidural, and not surprisingly, 54% of women 'needed' oxytocin augmentation. In this study, oxytocin use did not seem to affect VBAC rate.  The TOL mothers had lower complication rates than the repeat cesarean group.  "Trial of labor in selected cases of two or more low-segment cesarean sections may be considered safe for mother and fetus."  

Chattopadhyay, SK et al.  Planned Vaginal Delivery After Two Previous Cesarean Sections.  British Journal of Obstetrics and Gynaecology.  June 1994.  101(6):498-500.  

Saudi study.  115 women with 2 previous c/s were offered a trial of labor, and 90% had a VBA2C (the VBAC rate for after 1 c/s was only 54%!).  There were no ruptures but one scar dehiscence ('dehiscence') in the TOL group for a rate of 0.8%, which was comparable to the rate in the Elective Repeat Cesarean Section group (0.7%).  Labor was induced in about 1/3, but it was induced by PGE2 (prostaglandin gel) and pitocin was used only for augmentation (about 28%).  Unlike in many other studies, induction and augmentation did not significantly affect VBAC success rate.  

Cowan, RK et al.  Trial of Labor Following Cesarean Delivery.  Obstetrics and Gynecology.  June 1994.  83(6):933-6.  

593 women had a TOL after one or more prior cesareans, 81% overall had a VBAC.  There were 5 ruptures altogether (0.8% rate); 4 of the 5 were in the VBA1C group and 1 in the VBA2+C group.  39% of the TOLs had pitocin (11% induction, 28% augmentation).  3 of the 5 ruptures had pitocin (the text says 2 of 5 had pitocin but their own table of details on the ruptures indicates 3 of the 5 had had pitocin, which seems likely to be the more accurate report).  Of the total group, 80% of those with prior c/s for CPD/FTP had a VBAC, an unusually high rate.  87% of those with prior c/s for Fetal Distress had a VBAC, and a surprisingly low 69% of those with prior cesareans for breech had a VBAC.

75 of the women had a TOL after 2 or more cesareans.  The authors don't specify, but it can be derived that 59/75 had a VBA2+C for a 79% VBA2+C rate overall.  Further broken down, 56/72 women had a VBA2C (77%), and 3 women out of 3 had a VBA3C (100%).  There were no ruptures in the 3 c/s group, but there was 1 rupture in the 2 c/s group, making a rupture rate of 1.4% after 2 c/s or 1.3% after 2 or more c/s.  The woman  with 2 prior cesareans who ruptured did not receive pitocin, but she did have an unknown scar, raising the possibility that her scar was actually classical, which ruptures more often.  Her baby did fine despite the rupture.

The authors conclude that, "The number of previous abdominal deliveries a patient had undergone did not seem to affect her chance of delivering vaginally when given a trial of labor.  Women who had one, two, or three previous cesareans had vaginal delivery success rates of 81, 77, and 100%, respectively.  This seems to indicate that there is little or no loss of scar strength with repeat cesarean deliveries and that the number of previous cesareans should not be a factor in selecting women for a trial of labor."

Miller, DA et al. Vaginal Birth After Cesarean: A 10-Year Experience.  Obstetrics and Gynecology.  August 1994.  84(2):255-8. 

10 year study of VBACs (1983-1992), involving both VBA1C and VBAC after 2 or more c/s.  The largest sample size of VBA2+C yet.  1,827 women with 2 or more previous cesareans had a TOL; overall 75% of them had a VBAC (75% VBA2C rate, 79% VBA3+C rate).  The authors note strongly that the overall 75% VBA2+C averaged rate is significantly lower than the VBA1C rate (83%), and therefore these mothers should be counseled that they have a 'decreased likelihood of success'.  However, this is ridiculous since 75% (or 3/4!) did have a VBA2C, and that's a better VBAC rate than many VBA1C studies!  75% is an excellent success rate and would prevent 3/4 of unnecessary repeat cesareans, so discouraging 2+C women because the rate is slightly lower is a ridiculous point.  

However, of significant concern is that the rupture rate WAS higher in the group with multiple previous cesareans; it was about 3x higher than those with only 1 previous cesarean.  The rupture rate for VBA1C was 0.6%, 1.8% in VBA2C, and 1.2% in VBA3+C. The authors averaged the 2C and 3+C rates together and used the 1.7% average to show that the rupture risk was tripled in the multiple previous cesarean group.  However, the rate did not go up linearly; it was 1.8% after 2 c/s and 1.2% after 3 or more c/s (which should have been even higher if each successive c/s raises the risk of rupture significantly).  Nor did the study control for pitocin use; if women with 2 or more previous c/s were induced/augmented more, that might explain the higher rupture rate.  Furthermore, the study did not state the ERCS rate of rupture in women with 2+ c/s.  This might have been useful for comparison, since in women with 1 previous c/s the TOL rupture rate was 0.7%  vs. 0.5% in those who had repeat c/s; what was the rupture rate in ERCS moms with 2+ previous c/s?  Was it 0.5% like the 1 c/s group, or was it also increased like the TOL 2+ c/s group?  And therefore, how much of the risk is multiple scars vs. an actual trial of labor with multiple scars? On the other hand, the increased rate of rupture in the multiple cesarean group IS a legitimate concern, but just how much of a concern it is is unclear.

The authors do not really promote VBA2+C strongly, but neither do they forbid it.  Instead they note that the maximum benefit in lowering the national c/s rate would come from encouraging women with 1 previous c/s to VBAC; they note that a liberal TOL rate in the multiple c/s group might result in lowering the overall c/s rate by only 0.9%.  Therefore, they conclude, "Although trial of labor is a reasonable option with two or more low transverse or unknown incisions, it is best reserved for motivated patients who understand and accept the increased risk of uterine rupture and the decreased likelihood of success.  Active promotion of a trial of labor in women with two or more previous cesareans is unlikely to affect the cesarean rate appreciably.  Substantial reduction in the cesarean rate can be achieved safely and efficiently by encouraging a trial of labor in women with a single previous cesarean delivery."  Although the authors are lukewarm to VBA2C and are more concerned with lowering the overall c/s rate than the experience of the individual mother and child,  do note that they do support VBA2+C for 'motivated patients' if done with informed consent about possible risks.  

Asakura, H and Myers, SA.  More Than One Previous Cesarean Delivery: A 5-Year Experience with 435 Patients.  Obstetrics and Gynecology.  June 1995. 85(6):924-9.

Examined the records of 435 inner-city women in Chicago with >1 previous cesarean, and compared to those of 1206 women with only one previous cesarean.   'Allowed' a TOL in many women, including those with unknown scars, low vertical scars, and previous uterine fibroid surgery.  Oxytocin was 'liberally used' but not controlled for in the analysis.  Found a lower VBAC rate in women with multiple previous cesareans (64% vs. 77%), although it did note that the VBA2C rate was rising by the end of the 5 year study and was 74% in the last year, nearly that of the VBA1C women.  Dehiscence occurred slightly more often in women with multiple previous cesareans (2.0% vs. 1.1% in the TOL arm) BUT this did not rise to statistical significance.  There were 3 true ruptures in the TOL arm, for a 1% true rupture rate in those with multiple previous cesareans. The authors concluded that, "We believe that patients with more than one previous cesarean should be encouraged to undergo a trial of labor under guidelines similar to those proposed by ACOG for women with only one previous operation... [including] constant vigilance and attention to labor abnormalities."  

Davies, GAL et al.  Vaginal Birth After Cesarean: Physicians' Perceptions and Practice.  Journal of Reproductive Medicine.  July 1996.  41:515-520.

Interviewed the obstetricians practicing at an Ontario, Canada hospital to see if their perceptions about VBAC matched the realities of VBACs at that hospital.  95/124 patients at the hospital (77%) had a VBAC in 1991-92, while the doctors estimated about a 74% VBAC rate, which was pretty close.  20 women had had a prior vaginal birth; these women had a 95% VBAC rate, but even women who had not had a prior vaginal birth had a 73% VBAC rate.  Those with babies that weighed more than 4000g had a slightly lower VBAC rate (64%; it would be interesting to know how many of these were induced) but this did not reach statistical significance, and the authors found no association between fetal weight and VBACs. 25% were induced; the VBAC rate after induction was only 42% vs. 88% who went into labor spontaneously.  "Our findings suggest that induction of labor in patients attempting vaginal birth after cesarean should be performed only when absolutely indicated.  In those patients without a strong medical indication for induction of labor, awaiting the spontaneous onset of labor is recommended."

5 women in the study who had 2 prior cesareans chose a TOL, and 3/5 had a VBA2C (60%, lower but difference did not reach statistical significance).  There were no ruptures in either the VBA1C group or the VBA2C group. The OBs in the study were interviewed about their perceptions and policies regarding VBA2+C.  Interestingly, although their estimates of success were very close for VBA1C, their estimates of success for VBA2C were much too low.  The average estimate was 44%, while the rate at their institution was 60% (small sample).  The range of their estimates varied from 0% (apparently this doctor didn't think VBA2C was possible at all!) to 70% (which is about the average found in this FAQ's meta-analysis of VBA2C studies).  But taken together, they consistently underestimated VBA2C success rates, which is telling about many OB's attitudes.  25% of the OBs further stated they would not 'permit' a TOL after 2 cesareans, although 38% said they would, and 38% more would also offer VBAC to women with 3 prior cesareans.  Although the study is fairly small, it's an interesting commentary on how many doctors perceive VBA2+C. 

Bretelle, F et al.  Birth After Two Cesarean Sections: The Role of Trial of Labor.  Journal de Gynecologie, Obstetrique et Biologie de la Reproduction.  June 1998.  27(4):421-4.  [from abstract]

Retrospective 6-year study of women with 2 previous cesareans.  96 women had a TOL after 2 cesareans; the VBAC rate was 65%.  There were 3 dehiscences. It is not clear whether a distinction is made between dehiscences and ruptures; only 1 is listed as requiring surgery.  Therefore this is interpreted for now as a 3% dehiscence rate and a 1% true rupture rate.  Abstract does not specify pitocin use or non-use.  "Trial of labor after two cesareans is possible in the majority of cases.  Rate of vaginal birth is high and maternal and fetal morbidity is low."

Abbassi, H et al.  Trial of Labor After 2 Cesarean Sections.  Prospective Study of 130 Cases.   Journal de Gynecologie, Obstetrique et Biologie de la Reproduction. December 1998.  27(8):806-10. [from abstract]

130 women with 2 previous cesareans had a TOL, and 50% had a VBA2C.  Abstract does not specify amount of pitocin use or why the rate of VBACs was so much lower than most other studies. There were 4 dehiscences (3%)  and 2 true ruptures (1.5%), though none of these caused any perinatal death or morbidity.  The authors note that most of the dehiscences and ruptures were caused by "poor obstetrical conditions".  Although these are not specified, this usually means injudicious use of pitocin, labor unmonitored for long periods, delay in action when fetal heart problems or mother's knowledge of 'something wrong' is ignored, delay in surgery, etc.  The authors conclude that "Trial of vaginal delivery after two prior cesarean sections seems to us a reasonable attitude if it is well indicated and supervised correctly." 

Faridi, A and Rath, W.  2 or More Cesarean Sections---Elective Repeat Cesarean or Vaginal Delivery.  Z Geburtshilfe Neonatol. Jan-Feb 1999.  203(1):8-14.  [from abstract]

This article surveys and reviews the VBA2C medical literature.  It lists the rates of rupture as being between 0.0% and 2.8% in the studies.  The authors feel that epidurals are safe and effective for VBA2C, and the use of pitocin and prostaglandins are also appropriate.  They also state that, "The review of the literature suggests that a trial of labor in patients with more than one previous cesarean delivery is appropriate, and that these women should be treated no differently from those who have had only one cesarean delivery.  Obstetric management should be individualized after thorough patient counseling...The maternal and fetal outcomes in women who have had multiple previous sections do not differ from those in women after ordinary cesarean section."  

Caughey, AB et al.  Rate of Uterine Rupture During a Trial of Labor in Women with One or Two Prior Cesarean Deliveries.  American Journal of Obstetrics and Gynecology.  October 1999.  181(4):872-6.

Compared the rate of true rupture in women with 2 prior cesareans to that of women with one prior cesarean over a 12-year period.  3757 women with 1 prior c/s had a rupture rate of 0.8%, whereas 134 women with 2 prior c/s had a rupture rate of 3.7%.  (The VBA2C rate was 62%, vs. 75% for VBA1C in the study.)  Unlike many previous studies, this study DID control for possible confounding factors, like use of pitocin, birth weight, type of previous c/s, etc.  An interesting side note was that women with prior vaginal births were found to have only about 1/4 the risk for rupture as those without prior vaginal births. After analysis, they found that women with 2 prior cesareans had an almost 5-fold greater risk for rupture.  Labor lengths, pitocin use, epidurals, birth weights, etc. were all similar between groups.  

Although the rate of pitocin use was similar between groups, it would have been interesting to see at what point and in what dosages the pitocin was used in the two groups, given that Leung 1993 (above) found that most of their ruptures were in VBAC moms who were admitted to the hospital in early labor and often augmented aggressively with pitocin. Given the common labor restrictions and active management protocols in this country, further analysis of the discrepancy in uterine rupture rates would have been interesting. An important side observation is that these authors have published a series of studies on VBAC and rupture etc. in 1999-2000, and their overall rate of rupture seems to be running fairly high in most of the studies.  This doesn't negate their findings, but you do have to wonder why their rupture rates are falling higher than most other studies'.  

This study has caused a significant VBA2C backlash among many OBs, despite the fact that its numbers are much higher than other studies.   However, the authors do note that, "Although patients with 2 prior cesarean scars should be counseled differently from patients with 1 prior cesarean scar about their increased risk of uterine rupture and decreased chance of vaginal delivery in a subsequent trial of labor, on the basis of the evidence from this study and the existing literature, motivated patients may still wish to undergo a trial of labor.  Each patient and her provider must weigh the increased risk of uterine rupture against the benefits of vaginal delivery to determine the intended mode of delivery."  So the authors do not rule out VBA2C, despite their findings of increased rupture risk (a finding much higher than most other studies).  

Burke, AE et al.  Uterine Rupture During a Failed Trial of Labor: Are There Any Identifiable Risk Factors in Labor Management?  Obstetrics and Gynecology.  April 1, 2000.  95(4 Suppl 1):S42.  

Very small study that examined the cases of uterine rupture that occurred at Pennsylvania Hospital over a period of 10 years (there were 25 ruptures).  The next 'failed' VBAC after each rupture was selected as a control to compare the ruptures to, a common research technique but one that has some limitations.  The study looked to see if there were any identifiable risk factors in labor management that were common to the rupture cases.  They examined the role of maternal age, parity (number of pregnancies), labor management, and number of prior cesarean deliveries, but they found that patients were similar in most of these respects.  There was a trend towards significance in labor management.  56% of the ruptures were induced vs. 36% of the controls, and 36% of the ruptures had PGE2 (prostaglandin gel) vs. 20% of the controls, but this difference did not rise to statistical significance, probably because of the small size of the study.  Most importantly in relation to this FAQ, the number of prior low-transverse cesarean deliveries was not associated with uterine rupture in this study.

Other VBA2C Studies; Not Enough Info in Abstract to Analyze for This FAQ

Lawson, GW.  Vaginal Delivery After 3 Previous Caesarean Sections.  Australian and New Zealand Journal of Obstetrics and Gynaecology.  May 1987.  27(2):115-6.

Case report of a woman with 3 prior c/s 'permitted' a TOL.  Labor occurred spontaneously at 39 weeks; after an uneventful labor of 3.5 hours, a "Wrigley forceps lift-out was performed" (she gave birth, they used forceps).  "There was no maternal or neonatal morbidity and the uterine scar was intact."  This study was not used because it only reports one case.

Guettier, X et al.  A Uterus with Two Scars: Can We Allow Vaginal Delivery? J Gynecol Obstet Biol Reprod (Paris).  1992.  21(1):103-7.  

Study title seems to indicate that they allowed a TOL in women with 2 prior c/s, but the wording in the abstract is too ambiguous to confirm this.  It looks like 41 patients with 2 prior c/s were studied over the course of a year.  The abstract says that 17 patients "were put down for a tentative trial of labor" (so did they all have a TOL or not?), and that 9 did deliver vaginally (53%).  The wording is just too ambiguous to count for sure, so the study was not included in the FAQ's analysis.  However, the authors do conclude by saying, "This approach seems to have been reasonable and beneficial so long as proper precautions were taken.  The prognosis is better if there has been a previous vaginal delivery."

Bautrant, E et al.  Delivery After 2 Previous Cesarean Sections.  A Series of 41 Uterine Trials.  J Gynecol Obstet Biol Reprod (Paris).  1993.  22(5):543-7.

Had a 64% VBAC success rate, despite oxytocics in 96% of cases (!) and epidurals in 90% of cases.  Required a full obstetric team to be present throughout the whole labor, ready for intervention (obviously ready from the rate of oxytocics used!).  Not all the numbers add up correctly; there must be some errors in the abstract but the original study cannot be used to verify because it is in French.  Concludes that "it has become reasonable to carry out tests of uterine scars even after two scars have been made in the uterus because of the absence of any maternal or fetal complications in this series or in the literature."  This implies no ruptures, but this cannot be confirmed, so between that and the errors in the abstract, the study was not used.

Jamelle, RN.  Outcome of Unplanned Vaginal Deliveries After Two Previous Caesarean Sections.  Journal of Obstetrics & Gynaecology Research.  October 1996.  22(5):431-6. [from abstract]

This study is a puzzle and is difficult to know how to interpret.  It is a retrospective Pakistani study of 10 women who had had 2 previous c-sections in two years and then had a vaginal birth.  They were admitted late in labor (i.e. did not labor at the hospital; it is unstated in the abstract whether they had any prenatal care or any monitoring at all while laboring outside the hospital).  One patient had a dehiscence; no further information is given.  Since she apparently had a vaginal birth, it is unknown how the dehiscence was found; was there postpartum bleeding and problems due to an undiagnosed dehiscence/rupture?  Or did they manually explore the uterus afterwards to test the scar and then find a symptomless window or thin area (which would have little clinical significance)? The authors apparently oppose VBA2C because they say early in the abstract, "Twice a caesarean section always a caesarean section still stays put because of its high maternal and foetal complications."  This doesn't really make sense in light of what little information is in the abstract, nor are the study conditions or sample size adequate for making such conclusions.   Perhaps the authors state that at the beginning because it has been the prevailing opinion and they are trying to show it as wrong, or perhaps they are truly opposing VBA2C.  The abstract of this study is too unclear; therefore the study has been left out of most of the data analysis that Kmom did.  

Other Relevant VBAC Studies

Induction of Labor

Horenstein, JM and Phelan, JP.  Previous Cesarean Section: The Risks and Benefits of Oxytocin Usage in a Trial of Labor.  American Journal of Obstetrics and Gynecology.  March 1985.  151(5):564-9.

289 women who received pitocin (either for induction or augmentation) in a TOL were compared with 443 women who did not receive pitocin in their TOL.  VBAC rates were lower in the pitocin group, 69% vs. 89%.  This was especially strong in the groups with prior cesarean for CPD or Fetal Distress.  Among women with prior CPD c/s, the VBAC rate with pitocin was 65% vs. 81% without pitocin.  For prior c/s for fetal distress, the VBAC rate with pitocin was 55% vs. 98% in the group without pitocin.  There were no ruptures, but there was a somewhat increased rate of dehiscence among the pitocin group which did not reach statistical significance.  

Flamm, BL et al.  Oxytocin During Labor After a Previous Cesarean Section: Results of a Multicenter Study. Obstetrics and Gynecology.  November 1987.  70(5):709-12.

1776 women had a TOL after prior cesarean, and 27% had pitocin.  When pitocin was used, the VBAC rate was 64%, and when no pitocin was used, the VBAC rate was 78%.  The point at which pitocin was begun made a difference; the women who had pitocin at 0-2 cm (mostly coded as inductions) had a 56% VBAC rate. vs. 72% in women started at 3-4 cm and 64% in women started on pit at 5-10 cm.  This difference was most strong when stratified by reason for primary cesarean; pitocin had some effect on VBAC success rates when the first c/s was for breech, fetal distress, or 'other', but none of these reached statistical significance.  However, when the primary cesarean was for Failure To Progress (FTP, a.k.a. CPD too), those who 'required' pitocin had a 54% VBAC rate vs. a 70% VBAC rate among those who did not 'require' pitocin. 

The overall rupture rates in this series were quite low.  In the entire study, there were 3/1776 ruptures = 0.2% (one of the lowest rupture rates for that large a group around!).  2 of the 3 ruptures were found in the pitocin group, although there are no further details about when pitocin was started or what the dosage was, etc.  The rupture rate without pitocin was 1/1291=0.08% (nearly 0.1%) vs. 2/485=0.4% with pitocin.  Despite the fact that the rupture rate was 4x higher with pitocin, the small numbers of ruptures did not quite reach statistical significance.  However, the authors noted the trend, and stated that "future studies may reveal a slightly increased risk."

It is important that the authors here were trying to establish that if induction or augmentation were medically indicated, doctors did not have to proceed directly to an ERCS simply because of a woman's c/s history.  The authors state, "All obstetricians recognized that the need for oxytocin implies some factor or factors that lower the probability of vaginal birth.  Yet the prudent decision is generally to attempt labor induction or augmentation rather than proceeding directly to the operating room...[This and other studies] seem to indicate that the same policy should apply for women with a history of low transverse cesarean section."

Sakala, EP et al.  Oxytocin Use After Previous Cesarean: Why a Higher Rate of Failed Labor Trial?  Obstetrics and Gynecology.  March 1990.  75(3, pt.1):356-9.  

Examined 237 women with prior cesareans who had a TOL between 1984-1986; 73 received pitocin (almost 1/3) and 164 did not.  VBAC occurred in 89% of the women laboring spontaneously vs. 68% of those receiving pitocin.  When stratified by those being induced vs. those being augmented, the VBAC rate was 88% of the augmented group (similar to the no-pitocin group) vs. only 58% of those being induced.  There were no true ruptures in the study, although the dehiscence rate was 1% in the no pitocin group vs. 4%  in the pitocin group (this did not reach statistical significance, however, because of the small numbers).  Notes that the augmentation group started pitocin later (4.8 cm vs. 2.0 cm) and after some dilation and effacement had occurred on its own.  "We suggest that the success rate for previous-cesarean patients is more a matter of the cervical dilation when oxytocin infusion is started than a function of the use or non-use of oxytocin."

As a side note, the study reports 11 women with maternal diabetes (does not specify gd or type 1 or type 2) who had a TOL.  5/11 had a VBAC (45%); notes that the diabetic women were induced frequently.  

Segal, S et al.  Evaluation of Breast Stimulation for Induction of Labor in Women with Prior Cesarean Section and in Grand Multiparas.  Acta Obstetricia et Gynecologica Scandinavica.  January 1995.  74(1):40-41. [from abstract]

Retrospectively studied 135 women who were either grand multips (5 or more pregnancies) or who had a previous section.  Some had premature rupture of membranes, some did not.  All induced labor with breast stimulation.  84% had a VBAC.  "The duration of breast stimulation, length of labor, vaginal delivery rate, and Apgar score did not differ significantly among the four groups studied.  Breast stimulation in grandmultiparas and in women with a previous cesarean section is efficacious and safe."

Flamm, BL et al.  Prostaglandin E2 for Cervical Ripening: A Multicenter Study of Patients with Prior Cesarean Delivery.  American Journal of Perinatology.  March 1997.  14(3):157-60. 

Studied 5022 women who had a TOL between 1990-92, 75% of whom had a VBAC.  453 of these women were treated with PGE2 gel. Dosage was 2-4 mg intervaginally at approximately 4-hour intervals. Induction or augmentation with pitocin was needed in 77% of the PGE2 patients. Of the women receiving PGE2, 380 had had 1 prior c/s, 64 had had 2 prior c/s, 7 had had 3 prior c/s, and 2 had had 4 prior c/s.  (Unfortunately, no separate success rates or rupture data is available for these multiple cesarean groups.)  Of the group treated with PGE2 gel, 51% had a VBAC, vs. 77% for the group that did not receive PGE2.  

Uterine rupture occurred in 1.3% of those treated with PGE2 gel (6 of 453) versus 0.7% ruptures in those not treated with PGE2 (33 of 4569).   Although the rupture rate was increased, it did not rise to statistical significance.  Of note, all 6 ruptures in the PGE2 group had also been given pitocin as well.  "The use of PGE2 gel for cervical ripening appears to be relatively safe in patients with prior cesarean delivery."  (See further comments under Zelop study, below.)

Wing, DA et al.  Disruption of Prior Uterine Incision Following Misoprostol for Labor Induction in Women with Previous Cesarean Delivery.  Obstetrics and Gynecology.  May 1998.  91(5 pt 2):828-30.  [from abstract]

Authors planned a randomized trial comparing misoprostol (Cytotec) to pitocin for induction of  labor after prior cesarean.  When 2 of 17 women treated with Cytotec ruptured (12%!), the investigation was terminated prematurely 'because of safety concerns.'   The authors conclude, "When misoprostol is used in women with previous cesareans, there is a high frequency of disruption of prior uterine incisions." 

Rageth, JC et al.  Delivery After Previous Cesarean: A Risk Evaluation.  Obstetrics and Gynecology.  March 1999.  93(3):332-7. 

Examined a large database of births in Switzerland from 1983-1996 (40% of all Swiss births in that time).  Extracted data on women with prior cesareans who delivered either by elective cesarean or had a TOL. Of 17,613 women with a TOL, 74% had a VBAC.  The VBAC rate after induction was 66% vs. 75% with spontaneous labor.  The rate of rupture was 0.40% in the TOL group overall, but it was 0.65% in the TOL induction group, and induction was found to be significantly associated with uterine rupture.  The authors noted that although this rate was still relatively low, they recommended that "labor should be induced only if a clear indication is given." Unlike in most other studies, epidurals were also found to be associated with ruptures, but this is probably a reflection of the fact that most induced women end up with epidurals.  Failure to progress and abnormal fetal heart rate problems were also associated with ruptures, which are pretty well-established from other studies as well.  Ruptures were NOT found to be associated with prior cesarean for CPD, nor were they associated with macrosomia.  

There is lots of data to be extracted from this study; only the most pertinent points are mentioned in this summary.  VBAC rates depended a lot on the subgroups examined.  Fetal malpresentation was strongly associated with a 'failed' VBAC; it carried nearly 4x the risk for c/s after a TOL.  Only 42% of women with a fetal malposition had a VBAC.  Naturally, many of these were breeches, but some were also posterior babies too (baby facing mother's tummy instead of facing her back, which is easier for birth).  58% of women with posterior babies had a VBAC.  It is unstated how many of these babies turned to anterior for birth (which would increase the VBAC rate) and how many were born still posterior.  Although posterior babies had lower rates of VBAC, it is encouraging that more than half still ended up with a VBAC.  Big babies (macrosomia, >4000g) had a VBAC rate of about 66%, which was pretty good.  However, when induction and macrosomia were combined, the VBAC rate dropped to 57%---still better than half, but not as good as macrosomia alone.  The authors even recommend elective c/s if a baby is macrosomic and induction becomes 'necessary' (they don't specify what they mean by that; presumably they are not inducing simply because of baby's size but other complicating conditions), although Kmom strongly disagrees with this recommendation, ,since 57% is still better than half, and they do not similarly recommend elective cesarean for the posterior group, which had a VBAC rate of 58%.  The authors did not examine the rate of VBA2+C in this study, but implied in passing that the risks were high, yet cited VBA2C studies that supported VBA2C and showed the risks to be reasonable. Considering how large this database was, it would have been very interesting to have had VBA2+C TOLs studied as well; it's too bad they didn't do that.

Authors also noted that all women with prior cesareans (TOL or not) were more at risk for many problems in subsequent pregnancies, including  placental implantation disturbances (placenta previa, 2x the risk; placental abruption, 1.87x the risk in pregnancy, 1.49x the risk in labor), and other problems (hysterectomy, thromboembolism, fevers, more 'extrauterine' pregnancies, low Apgar scores for the baby, perinatal death, maternal deaths from placenta percreta, etc.) They caution against jumping to a primary cesarean too quickly or too lightly. "One of the main problems seems to be the quick decision to perform the first cesarean.  Consideration of cesarean should include not only the direct risks, but also the potential for late sequelae." 

Plaut, MM et al.  Uterine Rupture Associated with the Use of Misoprostol in the Gravid Patient with a Previous Cesarean Section.  American Journal of Obstetrics and Gynecology. June 1999.  180(6 Pt 1):1535-42. [from abstract]

Reviewed literature on the use of misoprostol (Cytotec) after prior c/s.  Found rupture occurred in 5/89 women with prior cesareans who were induced with misoprostol.  This amounted to a 5.6% uterine rupture rate (compared with a 0.2% rupture rate in those not receiving misoprostol).  "Misoprostol may increase the risk of uterine rupture in the patient with a scarred uterus.  Carefully controlled studies of the risks and benefits of misoprostol are necessary before its widespread use in this setting."

Rayburn, WF et al.  Weekly Administration of Prostaglandin E2 Gel Compared with Expectant Management in Women with Previous Cesareans.  Prepidil Gel Study Group.  Obstetrics and Gynecology.  August 1999.  94(2):250-4.  [from abstract]

Randomized multicenter investigation of women at term with one prior low-transverse c/s and an unfavorable cervix (Bishop score < or = 6).  143 women received 0.5 mg of PGE2 intracervically starting at week 39 and continuing once a week up to 3 weeks (control group did not, n=151).  Weekly doses did not bring on labor any sooner, did not shorten labor, and did not improve VBAC rates (57% vs. 55%).  No ruptures occurred.   The lack of adverse effect in this study may have been due to its smaller size and the low frequency of dosage.  Women here received a weekly dosage, whereas in many other studies, women receive doses every 3-4 hours.

Zelop, CM et al.  Uterine Rupture During Induced or Augmented Labor in Gravid Women with One Prior Cesarean Delivery.  American Journal of Obstetrics and Gynecology.  October 1999.  181(4):882-6. 

Examined the risk of uterine rupture during induction or augmentation in women with 1 prior cesarean over a 12-year period at a single center.  2774 women were studied.  560 (20%) had their labor induced by pitocin and/or prostaglandin gel.  1072 women had their spontaneous labors augmented with pitocin (39%).  Altogether, nearly 59% of the women in the study had pitocin or prostaglandin gel at some point in their labor.  (!)

The rupture rate for spontaneously laboring women who did not receive any pitocin augmentation was 0.4%, and  for spontaneously laboring women who were augmented with pitocin the rupture rate was 1.0%.  This increase, although substantial, did not rise to statistical significance.  Considering all spontaneously laboring women together, the rupture rate averaged out to 0.7%.  The authors suggest that their study may not have enough power to detect a tendency towards rupture that may occur with augmentation and "we suggest that the use of oxytocin proceed judiciously."

In contrast, the rupture rate for the women whose labors were induced was 2.3%, which certainly WAS statistically significant!  In a logistical regression model controlled for possible variables, induction with pitocin was associated with a 4.6x increased risk for uterine rupture.  The risk with prostaglandin gel induction was 3.2x (not significant).   Epidurals, birth weight, time since last birth, and duration of labor were all not associated with uterine rupture.  

In order of increasing rupture risk, the lowest rupture rates were seen in the spontaneously laboring group that had no pitocin augmentation (0.4% ruptures).  The overall study's rupture rate (induced, augmented, and totally spontaneous) was 1.0%; those who were induced by any means had an overall rate of 2.3% rupture. Those induced with pitocin only had a rupture rate of 2%, those induced with prostaglandin gel only had a 2.9% rupture rate (small sample, so it could be off), and those receiving both pitocin and prostaglandin gel for induction had a rupture rate of 4.5% (small sample, so it could be off).  This may have been a function of the aggressive dosages used; induction patients received 4 mg of prostaglandin gel every 4 hours (up to 3 doses) and then if pitocin was added, it was increased every 15-20 minutes!!  The combined effect of all these drugs (especially given so frequently) may well be behind that high rupture rate.

It is also important to note that the authors selected women with 1 prior c/s only and no other births, whereas Flamm's 1997 study on PGE2 use included 18% who had previously had a vaginal birth, and also some women with 2 or more prior cesareans.  In addition, Flamm's study did not really differentiate between induction and augmentation, which many authors have found to make a difference.  This is why the authors speculate that they found a relationship to rupture when Flamm did not. (Note that Flamm DID find a higher rate of rupture in the PGE2 group--1.3% vs. 0.7%--but it did not reach statistical significance.)

An important side observation is that these authors have published a series of studies on VBAC and rupture etc. in 1999-2000, and their overall rate of rupture seems to be running fairly high in most of the studies.  The rate of overall rupture in this study, for example, was 1.0%, which is higher than most VBA1C studies.  This doesn't negate their findings, but you do have to wonder why their rupture rates are falling higher than most other studies'.  Still, nearly 5x the risk of rupture from induction is quite significant.

Ravasia, DJ et al.  Uterine Rupture During Induced Trial of Labor Among Women With Previous Cesarean Delivery.  American Journal of Obstetrics and Gynecology.  November 2000.  183(5):1176-9.  

2119 trials of labor between 1992 and 1998 were evaluated for uterine rupture rates among spontaneously laboring women (n=1544) and induced women (n=575).  27% of the TOLs were induced, a rate that seems rather high compared to the relatively low rates in the 80s--- perhaps this is why rupture rates seem to have been increasing since the 80s?  The rupture rate for those in spontaneous labor was 0.45% vs. 1.4% with an induced TOL.  (Averaged, the rupture rate for both groups together was 15/2119=0.71%.)   

Analyzed further, the rupture rate associated with PGE2 gel was 2.9%, a relative risk for rupture of 6.41x.  This may, however, not just represent the risk from using PGE2 gel but from inducing on an unripe cervix.  Among other forms of induction, intracervical Foley catheter (a mechanical form of dilation) was associated with a 0.76% rate of rupture, labor induction no requiring cervical ripening was associated with a 0.74% rate of rupture, and the rupture rate associated with 'inductions other than with prostaglandin E2' was 0.74%. "Induction of labor was associated with an increased risk of uterine rupture among women with a previous cesarean delivery, and this association was highest when prostaglandin E(2) gel was used."

Hill, DA et al. Uterine Rupture and Dehiscence Associated with Intravaginal Misoprostol Cervical Ripening.  Journal of Reproductive Medicine.  October 2000.  45(10):823-6. [from abstract]

Two year retrospective chart review revealed a rupture rate of 3/48 or 6.3% in women given 50 mcg misoprostol (Cytotec). Rupture was found in 1/89 (1.1%) of those receiving pitocin induction, and 0/24 (0.0%) of those receiving PGE2.

Macrosomia and VBAC

Flamm, BL and Goings, JR.  Vaginal Birth After Cesarean Section: Is Suspected Fetal Macrosomia a Contraindication?  Obstetrics and Gynecology.  November 1989.  74(5):694-7. [from abstract]

Examined the old policy of restricting VBAC TOLs to those with infants estimated to be <4000g (not quite 9 lbs.).  The outcomes of 301 women who had a trial of labor with an infant that was >4000g were analyzed and compared with 1475 TOLs with birth weights <4000g and a control group of 301 women with macrosomic babies but no previous uterine surgery.  There were no significant differences in morbidity for mother or baby between groups (the rate of rupture was not increased in the macrosomic group).  58% of women with babies between 4000-4499g (8 lbs. 13 ounces to 9 lbs. 13 ounces) had a VBAC.  Of the women with babies over 4500g (more than 9 lbs. 14 ounces), 43% had a VBAC--nearly half.   Taking the two groups together, 55% of women with babies over 4000g had a VBAC.  The authors state, "The medical literature does not support elective cesarean section for suspected fetal macrosomia in nondiabetic women, and based on our experience, there appears to be no reason for treating previous-cesarean mothers differently."

Leaphart, WL, et al. Labor Induction with a Prenatal Diagnosis of Fetal Macrosomia. J Maternal Fetal Med. March-April 1997. 6(2):99-102.

Studied 53 non-diabetic patients who underwent induction for fetal macrosomia, and compared their c-section rate to the same number of women delivering a child of same or greater weight entering labor spontaneously. Theorized that since their institution has a low c/s rate, their induction c/s rate would not be different from their spontaneous labor c/s rate in women with babies of similar size. However, they were surprised to learn that the c/s rate in the induction group was double the rate in the spontaneous labor group (36% vs. 17%), despite lower overall birth weights in the induction group. In addition, the induction group that ended with a c/s had a lower birth weight than those who were induced and delivered vaginally (if birth wt. was such a big deal, it should be the other way around). 

Although the prior cesarean group studied was very small (n=14), only 2 of 7 (29%) who were induced for macrosomia had a VBAC, while 5 of 7 (71%) who had suspected macrosomia but labored spontaneously had a VBAC. Because of the extremely small sample size, this strong difference did not reach statistical significance but the authors noted the trend. Overall the authors concluded, "These data suggest that prenatal identification of macrosomia may lead to a higher rate of intervention and cesarean delivery.  Based on these data, we conclude that identification of macrosomia leading to intervention plays a more significant role in cesarean delivery than does actual birth weight...An increased risk of cesarean delivery was observed in subjects undergoing induction for the indication of fetal macrosomia. These data support a plan of expectant management when fetal macrosomia is suspected."

Abbassi, H et al.  Vaginal Birth After Cesarean Delivery: Can the Trial of Labor Be Extended.   J Gynecol Obstet Biol Reprod. June 1998.  27(4):425-9. [from abstract]

Restrospectively analyzed 1000 cases of previous cesarean mothers.  Among other things, questioned whether a TOL could be extended to potential VBAC TOL cases with breech presentation, 2 previous cesareans, twins, or suspected macrosomia.  862 women actually had a TOL, and 85% had a VBAC.  Of these, 75% of twin cases had a VBAC, 100% of breech cases had a VBAC, and 70% of macrosomic cases had a VBAC.  (Does not give the results of group with multiple previous cesareans; this is probably presented in the Abbassi 1998 study noted in the VBA2C references.) Authors list the rupture rate as 2.7%, 2/3 of which occurred in cases with unknown scars (might be classical, in other words, which tends to rupture more).  Excluding unknown scars, the rupture rate was 0.9%.  What percentage of ruptures occurred in each group (twins, macrosomia, etc.) is not specified in the abstract. The authors also do not mention controlling for pitocin use.  

Aboulfalah, A et al.  Delivery of Large Baby After Cesarean Section: Role of Trial of Labor.  Apropos of 355 Cases.  J Gynecol Obstet Biol Reprod (Paris).  June 2000.  29(4):409-13. [from abstract]

355 women with prior cesareans who gave birth to babies >4000g (not quite 9 lbs.) after a prior cesarean were retrospectively studied.  Those who had a TOL (n=297) were compared to those with ERCS and also to those in a TOL with average birth weight babies.  189/297 who had a TOL had a VBAC (64%).  There were 4 ruptures and 8 dehiscences (4/297=1.3% true rupture rate).  Authors state that the perinatal and maternal outcomes were similar between the TOL group and the ERCS group, but that the rupture rate was higher (and success rate lower) than in the TOL with non-macrosomic babies. This is one of the only studies were macrosomic babies had a higher rupture rate than non-macrosomic babies, but then the authors do not address in the abstract the rate of pitocin augmentation and induction in this group.  If large babies were induced more, then that would explain their higher rupture rate.  If the authors controlled for pitocin use, then this statistic has more meaning.  The full study is needed, but it is in French.

Usefulness of Pelvimetry

Thubisi, M et al.  Vaginal Delivery After Previous Caesarean Section: Is X-Ray Pelvimetry Necessary?  British Journal of Obstetrics and Gynaecology.  May 1993.  100(5):421-4. [from abstract]

Prospective controlled trial where women with prior cesareans were randomly allocated to either receive antepartum (before birth) X-Ray Pelvimetry (XRP) at 36 weeks, or to have a TOL first and then receive XRP after the birth.  Of the group who had pelvimetry before the birth, those with 'inadequate' pelvises by XRP were presumably all delivered by ERCS.  Those who were found to have an 'adequate' pelvis were presumably given a TOL; 23/84 had a vaginal birth (27%). Of the whole group that had pelvimetry at 36 weeks, only 23/144 had a vaginal birth, a VBAC rate of only 16%.  

Of the group that had a TOL first and pelvimetry after, 60/144 (42%) had a VBAC, a much higher rate (though still not great!).  Therefore pelvimetry before a TOL reduced the VBAC rate and increased the number of unnecessary cesareans. Most interestingly, 33/60 (55%) of women having a vaginal birth in the TOL group were judged to have an 'inadequate' pelvis afterwards and would have had an unnecessary ERCS had this information been given beforehand.  Furthermore, 74% of c/s in TOL group were judged to have had 'adequate' pelvises, yet had a c/s anyhow.  Pelvimetry was useless here, since more than half of those predicted to be 'inadequate' had a vaginal birth anyhow, and nearly 3/4 of those who had a TOL cesarean were judged to have an 'adequate' pelvis and should have given birth vaginally.

The authors conclude that "Antepartum XRP is not necessary prior to a trial labour in women with one previous caesarean section.  It increases the caesarean section rate and is a poor predictor of the outcome of labour."

O'Herlihy, C.  First Delivery After Cesarean Delivery for Strictly Defined Cephalopelvic Disproportion.  Obstetrics and Gynecology.  November 1998.  92(5):799-803. [from abstract]

Between 1975 and 1990, 42,793 women were delivered by cesarean for CPD at term.  Only 84 were found to meet the strict criteria for CPD (cervical dilation arrested after 5 cm, unresponsive to oxytocin augmentation after active dilation of 2 cm or more in 2 hours).  They did exclude fetal malpresentations and malpositions---someone admits that malpositions don't constitute true CPD!  Of the 84 women with strictly defined CPD, 40 had another baby at the same hospital and had a TOL.  27/40 (68%) delivered vaginally, despite supposedly having 'true' CPD, and 7 had larger babies than their first 'CPD' baby.  Of the 40 CPD mothers who had a TOL, 15 had previously had a c/s at full dilation (10 cm), but 11/15 (73%) went on to have a vaginal birth anyhow, and there was no serious maternal or neonatal morbidity.  The authors conclude that "The strictly defined diagnosis of nulliparous cephalopelvic disproportion should not constitute an automatic 'recurrent' indication for elective cesarean delivery."  

Long-Term Risks of Repeat Cesareans

Chattopadhyay, SK et al.  Placenta Previa and Accreta After Previous Caesarean Section.  Eur J Obstet Gynecol Reprod Biol.  December 30, 1993.  52(3):151-6. [from abstract]

Saudi study to check the relationship between prior cesarean and placenta previa and placenta accreta.  Studied 41,206 births, 1851 of which had had prior cesareans, and 222 had had placenta previa.  Placenta previa complicated 2.54% of cases with prior cesareans vs. 0.44% of those with no prior cesarean (about a 5x increase).  Those with prior cesareans who also had placenta previa were also more likely to have the placenta grow into the uterine wall (accreta); only 4.5% of previas in unscarred uteri developed accreta, vs. 38% in women with c/s scars.  Furthermore, the occurrence of accreta increased with the number of prior cesareans; previa was accompanied by accreta in 10% of cases with 1 prior scar, but 59% of those with 2 or more scars.  Also documents a maternal death in a woman with placenta previa accreta.   

Hemminki, E and Merilainen, J.  Long-Term Effects of Cesarean Sections: Ectopic Pregnancies and Placental Problems.  American Journal of Obstetrics and Gynecology. May 1996.  174:1569-74.

Retrospective cohort study based on two nationwide birth registers in Finland, with about 16,938 women who had had a c/s.  Looked at the first subsequent pregnancy and/or birth after the cesarean, then subanalyzed this by those who were primips (first-time moms) vs. multips (had prior births) at the first cesarean.  Found a reduced rate of fertility among those who had had cesareans (fewer completed pregnancies, more miscarriages, etc.).  Found a modest increase in ectopic pregnancies (1.28x risk) as well.  

More strikingly, found 4.5x the risk for placenta previa, although interestingly only in primips (most studies show it in both primips and multips with past cesareans).  Also showed a strong increase in placental abruptions among women with past cesareans; about 2-3x the risk in primips (depending on the registry used), and about 4x the risk for abruption in multips. "Cesarean section is a modest risk factor for ectopic pregnancy and an important risk factor for placental problems."

Ananth, CV et al.  The Association of Placenta Previa with History of Cesarean Delivery and Abortion: A MetaAnalysis.  American Journal of Obstetrics and Gynecology.  November 1997.  177(5):1071-78.  

Reviewed 36 studies between 1950 and 1996 for the occurrence of placenta previa and its relationship with c/s and abortion.  Found the that the average incidence of previa was about 0.36% or so until about 1985, after which it seemed to increase to about 0.48%.  Authors speculate that this could be because of the vastly increasing number of c/s showing up by then, or because of the increased rate of ultrasounds to detect it, or both.  Women with at least one prior cesarean were 2.6x more at risk for previa overall.  Women with a history of spontaneous or induced abortion also had a slightly increased risk for previa, about 1.6x overall.  

4 studies of 170,640 women studied the effect of the number of prior cesareans on placenta previa, and found a dose-response pattern.  With one prior cesarean, these 4 studies found a 4.5x risk for previa, after 2 c/s, the risk rose to 7.4x, after 3 c/s the risk was 6.5x, and with 4+ cesareans, the risk rose to nearly 45x the risk for placenta previa.  The authors conclude that, "This study provides yet another reason for reducing the rate of primary cesarean delivery and for advocating vaginal birth for women with prior cesarean delivery."  

Zaideh, SM et al.  Placenta Praevia and Accreta: Analysis of a Two-Year Experience.  Gynecol Obstet Invest.  August 1998.  46(2):96-8.  [from abstract]

Retrospectively reviewed 18,651 women giving birth from 1995 through 1996 in a hospital in North Jordan.  The incidence of placenta previa in women with unscarred uteri was 0.25%, vs. 1.87% in women with prior cesareans (avg. incidence for both groups combined was 0.35%).  The risk for previa increased as the number of prior cesareans increased; there was a 1.78% incidence after 1 prior c/s, 2.4% incidence after 2 c/s, and 2.8% after 3 or more c/s.   In addition, accreta was increased in women with prior cesareans as well; it was 9% (presumably 9% of the previas) in women with no c/s scar, vs. 41% in women with prior cesareans.  

Hendricks, MS et al.  Previous Cesarean Section and Abortion as Risk Factors for Developing Placenta Previa.  J Obstet Gynaecol Res.  April 1999.  25(2):137-42.  [from abstract]

Analyzed 16,169 pregnancies in Singapore from 1993-97.  1.0% overall had placenta previa (includes those with prior c/s).  Of the women with placenta previa, women with 1 prior c/s had a 2.2x risk for previa, women with 2 prior c/s had a 4.1x risk for previa, and women with 3 prior cesareans had 22.4x the risk for previa.  Abortion was also found to predispose towards previa.

Lydon-Rochelle, M et al. Association Between Method of Delivery and Maternal Rehospitalization.  Journal of the American Medical Association.  May 10, 2000.  283(18):2411-2416.

Retrospective cohort study of data from the Washington State Birth Events Database, 1987-1996.  Studied the relative risks of rehospitalization within 60 days of birth, a subject the authors noted has been understudied and may help provide information to providers and mothers about the "relative degree of maternal risk of the 2 approaches."  Found an 80% increased risk of rehospitalization after a c/s, and a 30% increased risk after assisted vaginal delivery (i.e. forceps, vacuum).  The risk for surgical wound infection with cesarean was 30-fold.  Women with cesareans were almost twice as likely as women with spontaneous vaginal births to be rehospitalized, for reasons such as uterine infection (2x risk), gallbladder disease (1.5x risk), urinary tract infections (1.5x risk), surgical wound complications (30x risk), cardiopulmonary conditions (2.4x risk), thromboembolic conditions (2.5x risk), and appendicitis (1.8x risk).  

While the risks after a cesarean were certainly increased, keep in mind that the overall occurrence was still relatively small, and should be kept in perspective.  Only 1.2% of women needed rehospitalization after birth overall (1.7% in the c/s group).  While wound infections were MUCH more common, rehospitalization still remained at only a 0.4% level for wound infection.  However, do note the comparison of rehospitalization numbers with uterine rupture numbers; 1.7% of c/s moms needed rehospitalization for something, and uterine rupture rates generally fall between 0.4%-1.0% for VBA1C and may go as high as 1-2% for VBA2C.  Interesting how rupture rates and their potential dangers get emphasized but similar figures for surgical risks get de-emphasized!

Interestingly, the study found future gallbladder and appendicitis problems associated with cesareans, something not previously reported on.  They noted that appendicitis may be associated with infections, and that "manipulation of abdominal contents during the cesarean delivery may exacerbate an existing subclinical infection."  They also note that gallbladder problems are associated with other types of abdominal surgery, and may be related to "stasis of bile with high viscosity induced by dehydration, hypovolemia [low blood pressure], fever, anesthesia, and narcotics, all of which may be associated with cesarean delivery."  So cesareans may be associated with a broader scope of potential problems than usually thought.

The authors conclude, "The use of safe, clinically appropriate strategies known to reduce cesarean delivery likelihood among primparous [first-time] women would provide primary prevention of cesarean-related morbidity.  Examples include provision of trained social support in labor, a larger role of midwives, low-dose bupivacaine epidural when labor pain management is necessary, second-opinion requirements on the necessity of cesarean delivery, and selective external cephalic version and moxibustion near term for breech presentation.  Among women with cesarean delivery, one strategy to prevent operative delivery-related morbidity is improvement of peripartal care management.  The likelihood of postcesarean endometritis or wound complications may be reduced by limiting the number of vaginal examinations during labor, use of assisted spontaneous placenta removal (external uterine massage and gentle cord traction), and antibiotic prophylaxis if labor or rupture of membranes has occurred...In addition to marking serious postpartum morbidity, maternal rehospitalization carries substantial consequences in and of itself, including high economic costs, the disruption of early parenting, and increased family burden."

Post-Term Pregnancy and VBACs

Yeh, S et al.  Postterm Pregnancy After Previous Cesarean Section.  Journal of Reproductive Medicine. January 1984.  29(1):41-4.  [from abstract]

Retrospectively analyzed 112 patients with prior c/s and 'postdates' pregnancy (abstract does not define 'postdates').  78 had a TOL. 73% had a VBAC, including 42% with a history of c/s for CPD.  Postdates pregnancy was NOT associated with an increased risk of uterine rupture.

Callahan, C et al.  Safety and Efficacy of Attempted Vaginal Birth After Cesarean Beyond the Estimated Date of Delivery.  Journal of Reproductive Medicine.  July 1999.  44(7):606-10.  [from abstract]

Studied whether it was safe for women to go past their due date in a VBAC TOL.  90 women who had a TOL between 1995-1996 and were at or beyond 40 weeks of gestation were identified; 66% had a VBAC.  Women who had had prior vaginal births had more VBACs (82% vs. 62%), and women of greater parity had more VBACs too.  "The patient and her family can be reassured that passing her due date does not alter the efficacy or safety of a trial of labor.  No change in counseling is warranted simply due to the completion of 40 weeks' gestation."

Zelop, CM et al. Outcomes of Trial of Labor Following Previous Cesarean Beyond the Estimated Date of Delivery.  Obstetrics and Gynecology.  April 1, 2000.  95(4 Suppl 1):S79. [from abstract]

Another in a continuing VBAC study series.  2,775 women with one c/s and no other deliveries were analyzed for outcome in relation to going into labor before the due date (EDD) vs. after it, and further stratified by induction vs. spontaneous labor.  1504 women birthed before the due date, and 1271 after the due date.  Of those in spontaneous labor before term,  75% had a VBAC and 0.5% ruptured, vs. 66% VBAC and 1.0% rupture after term. (Remember that 'spontaneous labor' can also include pitocin augmentation, and this would also need to be taken into account as well.  Were women past term augmented more often?)  Of those induced, 66% had a VBAC and 2.1% ruptured before term, vs. 57% VBAC and 2.6% ruptures after term.  Despite a somewhat higher rate of rupture after term, the authors note that "the risk of uterine rupture does not increase substantially after the EDD."

Comparing ERCS to TOL

Rosen, MG et al.  Vaginal Birth After Cesarean: A Meta-Analysis of Morbidity and Mortality.  Obstetrics and Gynecology.  March 1991.  77(3):465-70.

Did a meta-analysis of 31 studies between 1982-1989, for a total of 11,417 trials of labor.  Studied the association between birth route and the morbidity and mortality rates for mother and baby. Noted that many studies did not distinguish between dehiscence and rupture adequately and so was not able to analyze for these separately.  Also noted too little data to analyze for factors like more than one prior cesarean.

There was 'little difference'  in the rates of dehiscence/rupture between the TOLs and ERCS groups.  Women who had 'recurrent indications' for c/s (i.e. CPD) did not have higher rates of uterine dehiscence/rupture (actually, their rate was lower).  Women with low vertical scars had a dehiscence/rupture rate similar to that of women with low transverse scars, though the sample was small. Women with unknown scars did have somewhat higher rates of dehiscence/rupture, but this did not reach statistical significance. There was a higher rate of dehiscence/rupture with pitocin (2.3% vs. 1.5%) but this did not reach statistical significance and the authors stated that they were reassured to find 'no evidence' of an increased risk. (Yes, there was evidence, it just didn't reach statistical significance! Nor did they examine induction vs. augmentation risks.  In addition, pitocin dosing and frequency was used much more carefully with VBAC moms in the 80s, so this study doesn't necessarily mean that modern protocols do not increase risk.)  

When deaths before labor, birth defects, and prematurity were eliminated, there was 'no evidence of excess deaths among the trials of labor' (0.3% TOL, vs. 0.4% ERCS).  The study noted 3 perinatal deaths out of 22 true uterine ruptures in 5463 TOLs that had specific enough data for this subanalysis (0.4% rupture rate, 0.05%  fetal death rate).  Maternal risk was less with a TOL.  A successful TOL had the least risk for febrile morbidity, ERCS was in the middle, and an unsuccessful TOL had the most risk for febrile morbidity.  The authors note that, "Because about 73% of women undergoing a trial of labor after cesarean have a vaginal delivery, most women undergoing a trial of labor will have less febrile morbidity."  

Authors do note that studies on emotional and psychological effects of c/s and TOL were limited, and that "a large part of how a woman fares psychologically after any birth reflects how she integrates the birth experience, cognitively and emotionally, into the broader context of her life.  This may be a more difficult process for the mother who delivers by cesarean than for one who delivers vaginally.  We believe this...may deserve further attention." Finally, the authors conclude that "VBAC appears to be a safe component of obstetric care, and failed VBAC with consequent cesarean poses no major risks...Our findings argue for trials of labor for more women after a cesarean birth."

Parilla, BV et al.  Iatrogenic Respiratory Distress Syndrome Following Elective Repeat Cesarean Delivery. Obstetrics and Gynecology.  March 1993.  81(3):392-5. [from abstract]

Authors evaluated the incidence of iatrogenic (doctor-caused) Respiratory Distress Syndrome (RDS) after ERCS, and whether it was associated with 'departures from accepted management guidelines'.  Between 1986-91, there were 23,125 births, 1207 of which were by ERCS (no labor).  Of these, 18 'term' infants showed signs of respiratory difficulty and were admitted to the Neonatal Intensive Care Unit (NICU).  5 of 18 met the criteria for RDS.  Thus the rate of RDS in babies delivered by ERCS was 0.41%, a rate similar to the rupture rate of many VBAC studies, you'll notice!  4 of the 5 babies with RDS required a ventilator for 6+ days, and their NICU stays averaged 11 days.  Authors found several cases of iatrogenic RDS, caused by OBs not following accepted management guidelines for ERCS. Although Respiratory Distress Syndrome, like uterine rupture, is an uncommon occurrence, it DOES occur and is a significant risk of ERCS.  

AAFP Task Force on Clinical Policies for Patient Care.  Trial of Labor vs. Elective Repeat Cesarean Section. American Family Physician.  November 1, 1995.  52(6):1763-5. [from abstract]

A comprehensive review and meta-analysis of the literature was conducted.  It found that about 70% of women who undergo a TOL can expect a VBAC.  TOL was associated with a slightly increased risk of uterine rupture (0.24%), but a decreased risk of infection and fever (5.2%) and postpartum bleeding (0.59%).  There was also less risk of a newborn with an Apgar score less than 7 at five minutes (0.85%).  Financial cost was less with TOL.

Hook, B et al. Neonatal Morbidity After Elective Repeat Cesarean Section and Trial of Labor.  Pediatrics.  Sept.1, 1997.  100(3):348-53. [from abstract]

Compared the outcomes of babies born by ERCS (n=497) and those born by TOL, both VBAC (n=336) and c/s after TOL (n=156). Neonatal outcomes after a successful TOL were similar to routine vaginal births.  Infants born by c/s after TOL had a higher rate of infections. Babies born by ERCS were at increased risk for developing respiratory problems compared with those born by TOL.  A number of ERCS babies were iatrogenically premature (delivered supposedly at '38 weeks' but found after birth to actually still be premature). 

Mozurkewich, EL and Hutton, EK.  Elective Repeat Cesarean Delivery Versus a Trial of Labor: A Meta-Analysis of the Literature from 1989 to 1999.  American Journal of Obstetrics and Gynecology.  November 2000. 183(5):1187-97.

A follow-up to Rosen's 1991 meta-analysis of cesarean/TOL morbidity and mortality up to 1989.  Rosen found that a TOL did not significantly increase the rate of ruptures or fetal death.  However, rupture rates apparently rose in the 90s.  Mozurkewich and Hutton did a meta-analysis to evaluate the results of studies between 1989 to 1999. They analyzed 15 high-quality studies (37 others were excluded because many of the ERCS mothers were not eligible for a TOL, which makes a true comparison of outcome more difficult).  Many of these studies included women with more than one prior cesarean, although they did not do a subanalysis on this group.

They found that between 1989-1999, there was a slightly higher rate of rupture in women undergoing a TOL (about 2x the risk, though both absolute numbers are small--about 0.4% in the TOL group, and 0.2% in the ERCS group.).  They also found that the risk of fetal death was also slightly higher in the TOL group as well (about 2x the risk, though again the absolute numbers are small--about 0.2% in the TOL group and 0.1% in the ERCS group, excluding deaths that occurred before labor, those due to birth defects, and those due to prematurity).  However, there was less morbidity in the TOL mothers; they had less febrile morbidity (0.70x the risk), less need for transfusion (0.57x the risk), and fewer hysterectomies (0.39x the risk).

Do note that Rosen's 1991 study found no increased rupture rate or death risk; why did this change in the 90s?  Is it simply larger data pools to draw from, and thus more power to detect rupture rates?  Or increased rates of pitocin and other drugs, especially for induction?  Or less judicious selection of women for a TOL?  This analysis did not have the ability to answer these questions, but they are important ones to ask.  The study did not analyze for effect of pitocin use, which would have been a very useful subanalysis to have.  Is the rate of rupture really higher when little or no pitocin is used? 

However, either way, the risks of both TOL and ERCS are relatively small in absolute terms, and both are reasonable choices.  The authors conclude, "Our findings suggest that small increases in the uterine rupture rate and in fetal and neonatal mortality rates may result from a trial of labor with respect to elective repeat cesarean delivery.  These increases may be counterbalanced by reductions in maternal morbidity with a trial of labor, including febrile morbidity, transfusion, and hysterectomy.  Either a trial of labor or elective repeat cesarean delivery may be a reasonable option for women with at least one previous cesarean delivery." 

Miscellaneous VBAC Studies

Farmer, RM et al. Uterine Rupture During Trial of Labor After Previous Cesarean.  American Journal of Obstetrics and Gynecology.  October 1991.  165(4 Pt 1):996-1001.

Examined the charts of 137 women who had scar separations/ruptures between 1983-1989 at the USC school of medicine hospital.  70 of these were true ruptures, and 61 occurred in a TOL (out of 7,598 TOLs, or 0.8% true ruptures).  Of these, only 29 were known to be in low-transverse scars.  5 ruptures were known to be in women with classical scars, 2 had [low] vertical scars, and 25 more had 'unknown' scars. (L.A. has a population high in immigrants who often do not have documented scars, and while these are usually low-transverse, some countries do use classical incisions more regularly.)  So the true rupture rate for low-transverse scars was at least 0.7%, and probably lower than that.  The most important component of this study was the fact that 74% of the women who ruptured had received pitocin during labor.  The authors note that the incidence of pitocin use in women who did not rupture was not available, so they were not able to calculate any odds ratio or just how much of a factor pitocin really was. (It's probably a good bet it was probably pretty darn significant!) 

The authors also noted that the rupture rate in the TOL group increased significantly over the analysis period, from 0.4% in 1983 to 1.5% in 1989, and it increased every year except one where it inexplicably dropped back again, then right back up, higher than ever. They did not find any statistically significant change in labor duration, incidence of pitocin use, or number of previous cesareans in the population. (Wonder if the dosage, frequency, or timing of pitocin or multiple induction agents was a factor?)  The authors were unable to explain why the rupture rate increased, but it's encouraging that it apparently wasn't because of an increase in TOLs in women with multiple cesareans. 

There average number cesareans in the TOL group was 1.4 cesareans (authors give no specific breakdown, but note that most had 1 or 2 prior cesareans, with only 4 with more than two c/s).  No information is given whether any women with multiple cesareans were in the rupture group. One interesting side point is that this is one of the few studies that examines subsequent obstetric history of patients who had dehiscences or ruptures and more pregnancies later on. 

Jakobi, P et al.  Evaluation of Prognostic Factors for Vaginal Delivery After Cesarean Section.  Journal of Reproductive Medicine.  September 1993.  38(9):729-33. [from abstract]

Study used 15 prognostic factors to try to predict who might and might not have a VBAC in a TOL.  They analyzed 261 patients with one prior cesarean who had a TOL, and 6 factors were found to be significant.  The predictive value was great for predicting who WOULD have a VBAC but not good at predicting who WOULDN'T have a VBAC.  95% of those predicted to have a VBAC did end up having a VBAC.  However, only 33% of those predicted to 'fail' a TOL actually did so; 66% of those predicted to 'fail' a TOL actually had a VBAC anyhow.  "Because the chance of a successful vaginal delivery is >60% in women with a prediction of failure, until a selection criterion with a better prognostic value can be identified, a liberal approach to vaginal birth after cesarean section is justified even in this group."

Flamm, BL.  Once a Cesarean, Always a Controversy.  Obstetrics and Gynecology.  August 1997.  90(2):312-5.

Interesting discussion of the VBAC backlash of the late 90s.  Starts by discussing a history of VBAC, then goes on to discuss various VBAC controversies, such as the 'Risk Controversy' (discusses Denver and Salt Lake City case series where there were several fetal deaths), the 'Benchmark Controversy' (dissects the McMahon 1996 study that found higher complications in the 'failed' TOL group), the 'Ethical Controversy' (counseling dilemmas on VBAC vs. ERCS), the 'Legal Controversy' (discusses increased litigation over ruptures and the ominous VBAC consent forms/scare tactics that some doctors and insurance companies started using, decries these and returning to a no-VBAC policy, but endorses a more cautious approach), and the 'Appropriate Hospital  Controversy' (whether VBAC should be limited only to large hospitals with quick surgery response time--Flamm says no but urges hospitals to improve response times).  

Concludes that, "Clearly, there are risks to VBAC, but the aforementioned consent forms vastly overstate them.  A woman with a prior cesarean is at increased risk regardless of her mode of birth, and eliminating VBAC will not eliminate the risks.  Vigilance with respect to primary cesarean delivery is the only way to avoid this dilemma.  The young woman delivered by primary cesarean for 'lack of progress' in the latent phase of labor will have a permanently scarred uterus and will be at some increased risk during any and all future pregnancies.  For the moment, at least in some parts of the country, the pendulum seems to be swinging back toward routine repeat cesarean.  This may cause the national cesarean rate, which has been stable at approximately 22% for several years, to once again begin to climb. As the next century comes to a close, our descendants will no doubt look back at our current cesarean rates and smile.  The question is, Will they find our current rates ridiculously high or ridiculously low?"

Holt, VL and Mueller, BA.  Attempt and Success Rates for Vaginal Birth After Caesarean Section in Relation to Complications of the Previous Pregnancy.  Paediatric and Perinatal Epidemiology.  1997.  11(Suppl 1): 63-72.

Examined the records of all women in Washington State between 1987-1993 who had had a first birth by cesarean and a second live birth during that time.  Analyzed the data for the TOL rate and the VBAC rate in relation to the complications of the previous pregnancy.  For example, only 60% of women with previous macrosomic infants had a TOL in the second pregnancy; of these 55% had a VBAC.  Similarly, 60% of those with prior "CPD" cesareans had a TOL in the next pregnancy; 55% of these also had a VBAC.  74% of those with prior breech presentations had a TOL, and 75% of these had a VBAC. 69% of those with prior c/s for fetal distress had a TOL, and 65% had a VBAC.  64% of those with pregnancy-associated hypertension cesareans had a TOL and 54% of these had a VBAC.  68% of those with a 'failed induction' c/s had a TOL, and 51% of these had a VBAC.  60% of those with cesareans for placenta previa or abruptions had a TOL, and 73% had a VBAC.  70% of those with prior c/s for herpes had a TOL, and 66% had a VBAC.  (See the bottom paragraph for speculation why all these rates are so low.)

The rates were even lower for diabetics; only 51% of diabetics were 'allowed' a TOL, and only 36% of these had a VBAC (it would be interesting to see what kind of limitations were placed on these TOLs!).  Of those with gestational diabetes, only 58% were 'allowed' a TOL, and 46% of these had a VBAC (again, you have to wonder about the labor restrictions used for these extraordinarily low VBAC rates).  Note that this doesn't mean that only 36% of diabetics and 46% of gestational diabetics who have a TOL *will* have a VBAC; it means that under the policies of management and clear predisposition towards cesareans when any form of 'diabetes' is present, the VBAC rates were significantly affected.  Higher rates could probably be found with management and protocol changes; there is little to no data on diabetic VBACs, but what limited data on gd and VBACs exists shows that the rate is usually higher than 46%.  

The authors note that these VBAC rates are well below the success rates found in many VBAC studies, and speculate as to possible reasons.  Probably most importantly, these results are epidemiological, not prospective.  Many VBAC studies reflect a policy of trying to promote VBACs and/or lower the cesarean rates in certain institutions, and these VBAC rates tend to be 70-90% on average.  The studies where data is simply collected about how many VBACs actually occur without any special attention to VBAC success tend to have VBAC rates from 50-75% instead. That's probably what is reflected here, although these rates are particularly low in some groups even so.  Second, by limiting the data to those who had a first baby by cesarean and then the births after that, the authors note that they leave out women who had a prior vaginal birth before having a c/s, a demographic which tends to leave out a group with a high VBAC rate.  Both factors probably contribute.  In addition, the study looks at 1987-93, when VBACs were just beginning to come into more common practice.  There were still MANY limits on VBACs occurring in the late 80s and to a lesser extent into the early 90s, which may also lower VBAC rates specifically in groups seen at those points as being more 'at-risk' in VBACs, i.e. macrosomia, CPD, diabetes, inductions, etc. 

ACOG Practice Bulletin: Clinical Management Guidelines for Obstetrician-Gynecologists.  Vaginal Birth After Previous Cesarean Delivery.  Number 5, July 1999.  

Summary of the latest guidelines on VBACs from the American College of Obstetricians and Gynecologists.  Takes a step back on the VBAC issue, due to a VBAC backlash in the USA, including more malpractice suits.  Specifies information 'designed to aid practitioners in making decisions about appropriate obstetric and gynecologic care.'  These are not absolute rules, just information designed to help OBs make decisions, and guidelines for 'standard of care' within the profession.  

Gifford, DS et al. Lack of Progress in Labor as a Reason for Cesarean. Obstetrics and Gynecology.  April 2000. 95(4):589-95.

Authors reviewed medical records and did a postpartum telephone survey from 733 women with unplanned cesareans between 1993-94.  Measured the number of unplanned cesareans done for 'lack of progress' (i.e. FTP, dystocia, etc.) and how many of these conformed to the ACOG criteria for a diagnosis of lack of progress.  

Lack of progress was the reason given for 68% of these unplanned cesareans.  16% were in the latent (early) phase of labor according to ACOG criteria, and 36% of those who had cesareans at 10 cm did not have 'prolonged' second stage by ACOG criteria either. "Many cesareans are done during the latent phase of labor, and in the second stage of labor when it is not prolonged.  These practices do not conform to published diagnostic criteria for lack of progress."

Zelop, CM et al.  Effect of Previous Vaginal Deliveries on the Risk of Uterine Rupture During a Subsequent Trial of Labor.  American Journal of Obstetrics and Gynecology.  November 2000.  183(5):1184-6.

Reviewed the data on 3783 women who had a TOL after 1 or more c/s over a 12 year period.  58% had a VBAC (low rate!), and 0.8% had a rupture.  Of these women, 1021 had also had a previous vaginal birth, either before the c/s, between c/s, or after the c/s (prior VBAC). Authors found that those with prior vaginal delivery had 1/5 the risk of uterine rupture as those without a prior vaginal delivery (0.2% rupture vs. 1.1% rupture).  Authors noted that women without prior vaginal births did receive more pitocin augmentation and PGE2 gel (which might explain an increased rate of rupture), but after logistic regression analysis, these factors did not remain statistically significant.  In the group of 143 women with 2 or more prior cesareans, those with prior vaginal births had a rupture rate of 2.5% vs. 3.9% for those without vaginal births. This did not reach statistical significance, probably because of the small sample size, but the authors noted the trend for 40% lower risk of rupture among those with multiple cesareans who had had a prior vaginal birth.  However, prior VBACs did not constitute automatic protection against rupture; in the VBA1C group, there were 2 ruptures in women who had both had 2 prior VBACs.

General References on VBAC   

[Note: Most of these books are available from Cascade Books,, 1-800-443-9942.  This is your best first stop for childbirth-related materials.  Kmom is in no way related to their company, nor does she receive any kickbacks for promoting them, though she certainly ought to!  :-)   Other good sources include,,,, your local public library (have them do a search around your state), (La Leche League local chapters often have free lending libraries), or]

Korte, Diana. The VBAC Companion. Boston: Harvard Common Press.  1997.

THE best VBAC book available today.  A must-read!  Covers all the information needed to help choose between ERCS or VBAC TOL, and although clearly pro-VBAC, is supportive of women who choose ERCS.  Many helpful, practical hints for pursuing VBAC, choosing a provider, and addressing fears.  Outstanding!

Crawford, Karis and Johanne C. Walters.  Natural Childbirth After Cesarean. Cambridge, Massachussetts: Blackwell Science.  1996.  

Another excellent VBAC preparation book.  Practical and useful information, clearly written.  Available from  

Flamm, Bruce, M.D. Birth After Cesarean: The Medical Facts. New York: Simon and Schuster.  1990.  

Some of the information in this book is dated because it was written in 1990, but the book is still a valuable addition to VBAC literature.  Written by THE leading researcher on VBACs, the book tends to be a bit conservative in its recommendations but is still a good introduction to the subject.  

Goer, Henci. Obstetric Myths Versus Research Realities.  Westport, Connecticut: Bergin and Garvey.  1995.  More information at  Can also be ordered from Henci Goer, 970 Buckeye Court  Sunnyvale, CA 94086, or

Superb review of the medical literature and whether it supports most common obstetric practices on issues such as episiotomy, active management of labor, amniotomy, gestational diabetes, cesarean for breech, epidurals, etc.  Contains a MUST-READ section on VBAC vs. repeat cesarean.  

Baptisti Richards, Lynn.  The Vaginal Birth After Cesarean Experience.  South Hadley, Massachussetts: Bergin and Garvey.  1987.

Great book of anecdotal VBAC stories from mothers and providers.  Good for inspiration and 'you-can-do-it' motivation. 

Wainer Cohen, Nancy and Lois Estner.  Silent Knife. South Hadley, Massachussetts. 1983.   Hard-to-find these days, but Cascade Books still has some,, 1-800-443-9942.

An older book, the first on VBACs, and often angry in tone in places (but that's what was needed then!).  Unvarnished look at the pain that c/s deliveries often cause for mothers ("Voices of the Victims" is an especially powerful chapter); great for uncovering and starting to work through anger over previous births.  Because it was written in the early 80s, some of the medical information is a bit outdated, but most of it still rings very true and is valuable even today.  

Goer, Henci. The Thinking Woman's Guide to a Better Birth. New York: Berkeley Publishing Group (Perigee Book). 1999.  More information at Can also be ordered from Henci Goer, 970 Buckeye Court  Sunnyvale, CA 94086, or

Outstanding review of childbirth issues, especially induction.  Also has a pretty good section on VBAC vs. Repeat Cesarean, although OB Myths is better.

Koehler, Nan (written and compiled by). Artemis Speaks: VBAC Stories & Natural Childbirth Information.  Occidental, California: Jerald R. Brown, Inc.  1985.  Address listed for Jerald R. Brown, Inc. is 17440 Taylor Lane, Occidental, CA 95465. 

Book of VBAC stories and advice on alternative approaches to nutrition, pregnancy problems, etc.  Purposely samples different providers' opinions on nutrition, herbal advice, etc. so some info is contradictory.  Some is also out-of-date or dubious, so take with a grain of salt, but some may also be helpful.  Has wide variety of birth stories, from those that did not succeed to those that did against all odds.  Very difficult book to find.  Try searching for a used copy.

Processing Previous Births/Emotional Healing

Madsen, Lynn. Rebounding From Childbirth: Toward Emotional Recovery. Westport, Connecticut: Bergin & Garvey.  1994.

Good for specifically processing traumatic births, be they vaginal or cesarean, necessary or unnecessary.  A bit flakey in spots, but overall a very useful tool.

Panuthos, Claudia  and Catherine Romeo.  Ended Beginnings.  Westport, Connecticut: Bergin & Garvey.  1984.

Deeply affecting book about processing all kinds of pregnancy-related losses, including infertility struggles, cesareans, miscarriage, stillbirth, early neonatal death, etc.  Very hard to read the first time but definitely worth sticking it out and re-reading multiple times.  Offers suggestions for dealing with the pain of pregnancy losses on physical, mental, emotional, and spiritual levels, and help in moving beyond the losses and healing when ready.  Excellent book. 

Panuthos, Claudia. Transformation Through Birth.  Westport, Connecticut: Bergin & Garvey. 1984.

One of Kmom's all-time favorite childbirth books, an absolute MUST-READ for healing previous births or getting ready for a new birth.  Out-of-print now, but can still be found in used book stores (try or at Cascade Books,, 1-800-443-9942.

Freedman, Lois Halzel Freedman.  Birth As A Healing Experience: The Emotional Journey of Pregnancy Through Postpartum.  Binghamton, New York: Harrington Park Press.  1999.

A new book on the emotional aspects of pregnancy and postpartum, emphasizing the opportunity for healing potential.  Utilizes many individual women's stories.  A good introduction to the subject, but even more detail and stories would have been helpful.  The author is a certified childbirth educator with a private practice in individual prenatal and postpartum counseling in the Boston area.  

Wainer Cohen, Nancy. Silent Knife.  See above. Also hard-to-find these days, but Cascade Books still has some,, 1-800-443-9942.

Capacchione, Lucia and Sandra Bardsley.  Creating a Joyful Birth Experience: Developing a Partnership with Your Unborn Child for Healthy Pregnancy, Labor, and Early Parenting.  New York: Simon and Schuster.  1994.

A childbirth preparation guide with an emphasis on emotional preparation too.  Uses many "New Agey" exercises like artwork, writing with your non-dominant hand, imagery and visualizations, etc. to work through issues, but if you can get over a resistance to the 'crunchiness' of some of these techniques they can really be helpful.  Unfortunately, the book is not easy to find but may be available still from or   

Siegel, Bernie S.  Peace, Love, and Healing.  New York: Harper & Row.  1989.  Also wrote Love, Medicine, and Miracles.  

Not a childbirth book, but has a lot of insight into the effect of emotional issues on the body, and how to utilize the innate ability to self-heal the soul (and often the body) through various techniques.  Author is a surgeon who has worked extensively with cancer etc. patients and studied the techniques of visualization, meditation, etc. in conjunction with traditional treatments.   


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