NIH Consensus updates on VBACs

One of the advantages to being a midwife is being on all kinds of funky mailing lists, which means that all softs of health information, conference invitations, and sometimes even free samples often show up on my doorstep.  A few days ago, I got just such a mailing– the NIH Consensus Development Conference Statement on Vaginal Birth After Cesarean: New Insights. Granted, this is from 2010, but nevertheless represents the most current and updated NIH State-of-the-Science statement to date.

A consensus panel of 15 non-advocate representatives (i.e. not lobbyists) from different disciplines (obstetrics, gynecology, pediatrics, maternal and fetal medicine, midwifery, clinical pharmacology, medical ethics, nursing, anesthesiology, risk management etc. etc.) got together and performed a thorough literature review and listened to presentations by experts, and then drafted the consensus report, posted above.  Pretty nifty, given the amount of information they had to wade through, and the fact that not all of the research available is good research.  I really liked the fact that the statement divides all of its research up into “High Grade of Evidence”, “Moderate Grade of Evidence”, “Low Grade of Evidence” and “Insufficient Evidence”.  My only complaint is that there isn’t actually a reference list at the back of the statement, and none of the research papers they are discussing are actually cited, so it makes it much harder to find and look at the research yourself.

And what does it say?  Basically, that the VBAC rate is still plummeting, and more research is needed.  Big surprise there.  The VBAC rate has been plummeting for decades, ever since its record high in 1996 of 28.3%.  It also seemed to suggest that ACOG could play a much bigger role in encouraging the practice of VBACs again, but maybe that was just my wishful thinking.

The statement begins by systematically reviewing the evidence behind the short-term and long-term benefits and harms of trial of labor v. repeat cesarean from the perspective of both mothers and babies.   Some of the benefits of trial of labor for mothers includes a decreased risk of maternal mortality when compared to repeat cesarean (high grade of evidence).  There is also a lower risk of hysterectomy (moderate grade of evidence), lower incidence of placental complications with future pregnancies, such as placenta previa, and placenta accreta/ increta/ percreta, (moderate grade of evidence), and shorter hospital-stays, with possible decreased risks of DVT (low grade of evidence).  Among the risks of trial of labor for mothers includes incidence of uterine rupture (moderate grade evidence), which is increased if there is a classical incision, i.e. a vertical uterine scar (however, there was only low-grade evidence to support this).  It’s also interesting to note that there was insufficient evidence to support the claim that repeat cesareans help avoid future pelvic floor dysfunction.

From the babies perspective, the perinatal mortality rate and neonatal mortality rate were observed to be lower in babies receiving repeat cesareans as opposed to trial of labor (moderate grade of evidence), and slightly higher rates of hypoxic eschemic encephalopathy in babies receiving a trial of labor (low grade of evidence).

To my way of thinking, though, the more important part of this statement is the fact that it also looked into many of the non-medical factors that are influencing the declining VBAC rate, such as professional association practice guidelines (ACOG’s 1999 Practice Guideline on VBAC being a big one), hospital and health-insurance policies, and professional liability concerns among physicians and hospitals.  I have heard my OB colleagues joke among themselves that the only bad cesarean is the one that isn’t done.  The general outlook that I have observed seems to be that doing a cesarean is always the right way to go from a medical-legal perspective; cesareans are perceived as being safer, by doctors and patients, no matter what the situation, and if in doubt, it’s better to err on the side of doing a cesarean than not.  This attitude can be found all over the place.  To quote a comment made by an obstetrician on KevinMD.com: “You never get sued for doing a cesarean section, you get sued for not doing one. So given the scenario with a questionable fetal heart rate tracing where any “expert witness” can find fault with, (even if there is none) I would rather perform a cesarean section than not. It comes down to a matter of staying in practice and making a living.”

The last Practice Guideline that ACOG has issued on the subject came out in 1999, and reversed its prior encouragement of VBACs, instead saying that women should be “offered” (rather than “encouraged” to have) a trial of labor if there are no contraindications, but basically asserting that it’s a personal decision, and can be decided on between doctor and patient on a case-by-case basis.  The 1999 Practice Guideline also stated that trials of labor should only be done in hospitals ready to respond to emergencies with on-call physicians always available to perform an emergency cesarean, as well as 24-hour on-call anesthesiology coverage (a standard which many rural and smaller hospitals find very difficult to comply with).   It’s important to note that this recommendation was rated as a Level C in the ACOG Guideline (i.e. based on consensus expert opinion, with no hard evidence to support it).  Nevertheless, many hospitals and providers have cited the lack of these emergency provisions as the reason that they no longer offer women trials of labor.

In it’s conclusion, the NIH consensus report directly addresses this issue:

Given the low level of evidence for the requirement of “immediately available” surgical and anesthesia personnel in current guidelines, we recommend that the American College of Obstetricians and Gynecologists and the American Society of Anesthesiologists reassess this requirement with specific reference to other obstetric complications of comparable risk, risk stratification, and in light of limited physician and nursing resources.

We now know so much more about the causes of uterine rupture and the safety of VBACs than we did 20 years ago when the practice was first encouraged.  We know that the use of prostoglandin induction agents such as cytotec and cervadil were a chief cause of uterine rupture, and that women with low-transverse uterine incisions actually have a pretty low rate of uterine rupture.  With this in mind, it’s probably time for ACOG to finally issue a new Practice Guideline on VBACs.

A last comment about the NIH report: they left a laundry list of critical gaps missing from the research, highlighting the places where more information is desperately needed, which was nice to see.  They also issued a few choice words about the “cesearean as best defense” mentality:

We are concerned that medical-legal considerations add to, and in many instances exacerbate, these barriers to trial of labor.  Policymakers, providers, and other stakeholders must collaborate in developing and implementing appropriate strategies to mitigate the chilling effect the medical-legal environment has on access to care.

I couldn’t agree more!  Thank you, NIH, for a well-written and informative report.  Maybe this will help swing the momentum back in favor of VBACs again!