Is Elective Repeat Cesarean Surgery Truly Safer Than Planned VBAC?

The headline on a recent BBC News health article reads: “Planned repeat C-sections ‘safer.’ The article goes on to report on two studies that appear to support that conclusion, but do they really? Let’s see what the article says and follow with a look at the actual studies.

One of the studies, the BBC News article tells us, is a U.K. study of 159 cases of uterine rupture in which 139 occurred in women with a prior cesarean. The risk of scar rupture in women with a prior scar, it reports, was seven times greater in women having VBAC labors compared with women planning repeat cesareans, and the risk of the baby dying was three times higher.

That would seem to make a clear case for elective (no medical indication) repeat cesarean (ERC), but if we turn to the study itself, we find that the risk of scar rupture in a VBAC labor was 2 per 1000 VBAC labors versus 0.3 per 1000 planned repeat cesareans, or roughly 2 more scar ruptures per 1000 VBAC labors, not the large difference that “seven times greater” suggests. Moreover, the likelihood of scar rupture was influenced by modifiable factors. The use of prostaglandin, oxytocin, or both for initiating or augmenting labor increased the risk without improving the VBAC rate. In fact, misoprostol was the induction agent in 18% of induced women experiencing scar rupture, but none of the women not having scar rupture were given this agent. ACOG’s 2006 induction guidelines for VBAC labors prohibits using misoprostol because of its strong association with scar rupture. Furthermore, study authors theorize that one reason the scar rupture rate was so low in their study compared with some others was because double-layer uterine suturing, another modifiable practice, is the norm in the U.K..

As for VBAC labor tripling the rate of perinatal (intrapartum + neonatal) death compared with ERC, the study doesn’t give us this number (or maternal morbidity or mortality rates either, for that matter). The study actually only reports maternal and perinatal outcomes in the population overall, which included 20 women with rupture of an unscarred uterus, an event that may be more likely to produce severe adverse outcomes than a scar rupture. In addition, some of the neonatal deaths in women with prior cesarean may have been in women having emergent nonlabor cesareans. For example, three women had a scar rupture in conjunction with placenta previa. The extensive NIH systematic review  of VBAC reported that 6% of babies died as a result of scar rupture in a VBAC labor. We can use that number to calculate the odds of a baby dying in a VBAC labor in the U.K. study by multiplying it (0.06) by the U.K. study’s scar rupture rate (0.002). The result equals 0.00012 or 1 perinatal death per 10,000 VBAC labors. To be sure, every death is a tragedy, but we must also put this into perspective: that mortality is equivalent to the maternal mortality rate with ERC, which is 3 per 10,000, and much less than the fetal loss rate as a result of having an amniocentesis, which one modern-day study found to be 60 per 10,000.

The other study, according to the BBC News article, is an Australian study  of more than 2000 women planning their second delivery after a first cesarean. The BBC article states that the planned VBAC group had more stillbirths, and women were more likely to have severe bleeding, but gives no numbers.

Again, let’s turn to the actual study. The two planned VBAC deaths were unexplained fetal demises in infants born at 39 weeks, the implication being that ERC before that gestational age would have averted them. Perhaps they would have, but as the study  I analyzed in another blog post found, ERC at 39 weeks would have prevented only two of the six antepartum deaths.

The excess in severe hemorrhage (defined as > 1500 ml or transfusion) amounted to 1.5 more instances per 1000 VBAC labors, again, a small absolute difference, and a difference, moreover, that probably would have favored planned VBAC had not so few women had vaginal births. Maternal morbidity mostly occurs in labors that end in intrapartum cesareans, and the VBAC rate in this study was a dismal 43%. With physiologic care, the rate could have been as high as 81%. Even with typical management, studies have reported rates ranging from 61-72% in women with no prior vaginal births. In any case, however worrisome at the time, no differences were found in permanent sequelae such as hysterectomy.

And there is more: neither these studies nor the BBC news article considers the downstream consequences of accumulating cesarean scars, but they should. Even women who plan no more children may change their minds or continue with an unplanned pregnancy. According to the NIH systematic review, as the number of cesareans rises so does the risk of serious neonatal and maternal morbidity and perinatal mortality. By contrast, once a woman has a VBAC under her belt, so to speak, she is almost certain to go on having uneventful VBACs. Also, the review found that the risk of forming dense adhesions (internal scar tissue) rises with number of cesareans as well, thus increasing the likelihood of chronic pain and making any future abdominal surgery, not just future cesareans, more risky and difficult. Add these considerations into the mix, and the balance tips toward planning VBAC as the safer option for almost all women.

Headlines and articles like the one from the BBC News obstruct informed decision making by obscuring the true degree of comparative risk, and the studies contribute by failing to emphasize that better labor management in the previous delivery and current labor would improve outcomes. Planned VBAC is not without risks, but neither is ERC. Women deserve accurate, complete, and, most importantly, quantified information on which to decide on mode of birth after a cesarean. They also should have care in the primary cesarean that promotes safety in future VBACs and care in VBAC labors that promotes safe, healthy vaginal birth. To do less than that does women and their babies a serious disservice.

Cesarean Birth

  1. | #1

    Great post! It was very helpful how you broke everything down and compared it. It is so frustrating to see articles published with information that is incorrect or exaggerated.

  2. | #2

    Dear Henci,
    Thank you for this analysis. Once again, we can count on you to separate OB myth-making from reality. This is an excellent dissection of the articles in question, and I will forward this on to the Big Push for Midwives list and facebook page and to others.
    Best regards,

  3. | #3

    I too want to thank you for analysis, I read a blurb about this study in the NY Times and was furious no mention of “inductions”.
    I wish you would send this to the Times, maybe they would publish it next week in the science section! http://www.nytimes.com/2012/03/27/health/research/slight-risk-in-vaginal-birth-after-c-section.html?_r=1&scp=1&sq=Vaginal%20Birth%20After%20Cesarean&st=cse

  4. | #4

    You’re welcome! I’m glad that my analysis has been helpful.

  5. avatar
    | #5

    Thank you so much for these facts and this analysis. Great work.

  6. avatar
    Fernando Molina
    | #6

    Thank you very much Henci for such great analysis. I am a Family Physician and male Midwife in Venezuela, dedicated exclusively to homebirths, with many VBACs. In this country 90% c-section rate in private hospitals. With your permission i will use the article and your analysis in my prenatal classes. God Bless you

  7. avatar
    | #7

    Thank you Henci for some SENSE AND SENSIBILITY.

  8. | #8

    Thank you Henci well described and thougtful contribution.

    Your mention of Misoprostol, a cancer treating agent reminds me of how many years ago Marsden Wagner warned us of its use in this mysterious and hidden gel (inserted in the vagina unnoticeable). The suppression of the immune system as a result of the combination of induced labour and chemicals, led to frightening tissue destruction due to bacterial opportunistic infection after Caesarian Birth. One doctor at a major teaching hospital in Melbourne where I worked as a midwife educator was moved sideways for cavalier practice which reulted in near death of the mother and a moribund baby. This doctor moved to a far North West country town in Victoria. It was reported that he introduced the Cytotec gel (mysteriously called prostaglandin or initials ?P02)and in contradiciton to hospital protocol gave a sytocinon infusion under 6 hours. Result two ruptured uterine organs and loss of two babies. This man then transfered to the the South East 30 years on in my local area he continued to practice as a gynaecologist causing even more harm. I have made submission for Obstetric Hospital Review of Australian Hospitals OPRAH with minimal respnse. Why do women accept these practices without investigation?

  9. | #9

    Again, you’re welcome. I’m glad to have been of service.

  10. | #10

    @Beverley Walker
    Misoprostol (trade name: Cytotec) is a troubling induction agent, as I have written in blog posts for S&S: http://www.scienceandsensibility.org/?p=1189, but some of your information is not correct. It is not a cancer treatment, but an ulcer medication, and so far as I know, it is not associated with infection. I think you have also confused misoprostol with prostaglandin E2, often abbreviated PGE2. PGE2 can be formulated as a gel, but misoprostol is a tablet. We agree that women should be asking questions and making informed decisions about their care.

  11. avatar
    | #11

    Thank you so much for getting some truth out there on the “studies”! So often I hear people quoting the information incorrectly and scaring women and families. Women need truth to base their individual decisions on for their own care. It is so sad to not see VBAC’s as an option for so many women, but the risks of Repeat C-sections not be addressed.

  12. | #12

    You’re welcome! Sometimes the problems lie in the studies themselves, but more often, as in the case here, the problem is how the news media report on the study.

  13. avatar
    | #13

    I agree that it is interesting to balance others points of view against the research. However, I think you are guilty of bias yourself…

    About the first study: Yes, as you pointed out an extra 2/1000 uterine ruptures per VBAC labours. Well I think that is significant! Your risk in VBAC is 1/500 while is 1/3300 for ERC (Both compared to only 0.03/1000 in women without a previous caesarian.) So the 7 times risk is relevant to prospective mothers choosing what to do. You can’t under report it whatever your view.
    Furthermore, yes, labour with induction or oxytocin was riskier for uterine rupture. BUT, without induction or oxytocin the risk was still 1.3/1000 in labour versus 0.3/1000 in ERC. That is still significant.

    The Australian study was excellent in my view, but, I agree, was somewhat carelessly reported by the BBC. However, looking at the data the BBC’s conclusions were not “wrong”.

    Lastly, you mention that neither study mentions the “downstream consequences of accumulating caesarian scars”. Correct. BUT, they have not mentioned the very common downstream consequences of normal labour either like urinary incontinence, sexual dysfunction, and uterine prolapse which blight so many women’s lives either. And they are important too.

    I agree that women need accurate and complete information to help them to decide what to do. Well, I have to decide VCAC vs ERC- and all I have been given by my midwife so far is an A4 sheet explaining that VBAC is better except for the risk of uterine rupture. What it doesn’t report is my massive risk (maybe 22%) of induction and/or massive risk (25-50%) of caesarian after trail of labour- which means that overall there is a very high probability that I might need an induction and then go on to have an emergency caesarian. This route has a much worse outcome (as the research shows) than an ERC, and to my mind is to be avoided as a priority. Yes, you are right about quantifying the risk – but with those probabilities against me why on earth would I choose a VBAC?

  14. | #14

    As I pointed out, “7 times the risk” is an alarmist way of presenting statistics. More accurate for making judgments is the absolute difference, i.e., how many more women per 100 or 1000 or 10,000 will experience this complication? which is why I presented the data as 2 more scar ruptures per 1000 VBAC labors. This isn’t “under reporting,” merely accurate reporting free of the emotional charge “7 times” conujures up. And certainly some women will judge that risk to be unacceptable, as apparently you do.

    Turning to the consequences of vaginal birth for the pelvic floor, common beliefs about its effects are not supported by the research. You can find research-based information at http://childbirthconnection.org/article.asp?ck=10166&ClickedLink=274&area=27#pelvic and at http://childbirthconnection.org/article.asp?ck=10206.

    I’m not sure why you believe there is a “massive risk” of induction in a VBAC labor. There shouldn’t be. Even for women without a scarred uterus the common reasons for inducing labor either aren’t supported by the research at all or are debatable, and inducing VBAC labors is more problematic because it both increases risk of scar rupture and decreases likelihood of vaginal birth. If you would like to tell me more about why you think induction is likely to be required, I’d be happy to discuss this further.

    If you are looking for current, research-based information on the tradeoffs of elective repeat cesarean and planned VBAC, you can’t do better than http://childbirthconnection.org/article.asp?ClickedLink=293&ck=10212&area=27.

    Whatever you decide, I wish you a safe, healthy delivery.

  1. | #1