Study Finds VBAC "As Safe" As Repeat Cesarean
Note: I wrote this in early 2006 before I had my VBAC at home in November 2007.
As someone who is planning a vaginal birth after cesarean (VBAC) with my next child, I am always reading the latest research studies about the risks of VBAC vs elective repeat cesarean section.
All the studies I have read thus far found uterine rupture rates, ranging from 0.5% to 0.7%, in women with one prior low uterine segment (”bikini cut”) cesarean. So you can imagine my excitement when I read Results of a Well-Defined Protocol for a Trial of Labor After Prior Cesarean Delivery published recently in Obstetrics & Gynecology. The doctors encouraged women who have had one bikini cut cesarean to undergo a trial of labor (TOL) after the spontaneous onset of labor unless cesarean section (CS) delivery was medically indicated. Unless there were maternal or fetal conditions that made delivery immediately necessary, they waited for spontaneous labor or 42 weeks.
They used Bishops scores if delivery was needed before spontaneous labor. Less than 6 (unripe) had a CS while greater than 6 (ripe) had an induction. They stated that artificial rupture of membranes (AROM) was the preferred way to induce vs. induction with pitocin. They did not use prostaglandins, Foley catheters, or Misoprostol (Cytotec). They did not induce an unripe cervix. They did use pitocin for augmentation but used a max of 20 mU/min. 60 (7.1%) women were induced with either AROM or pitocin. 128 (15.2%) were augmented with pitocin.
Of the 841 women who attempted a vaginal birth, they only had 1 uterine rupture 18 hours after vaginal delivery. That woman had an uneventful course for 16 hours when her blood pressure and percentage of red blood cells dropped. She had a laparotomy and a 4 cm rupture was found on the left uterine wall. They did not state if the previous cesarean incision was involved in the rupture.
One woman in the CS group had a hysterectomy due to placenta accreta. One woman in the CS group and two women in the TOL group who had a repeat CS had abdominal surgery due to post partum hemorrhage. They stated an overall rate of major complications of 1.3% in the planned CS group and 1.8% in the TOL group. However the difference was not statistically significant (p=0.50). They also stated that all but two of the major complications in the TOL group were in women who had a repeat CS.
The median hospital stay was two days for the TOL group while in the planned CS group, the median was four days. This was statistically significant (p<0.001). The NICU admissions were 2.4% for the TOL group and 4.3% for the planned CS group. This was not statistically significant but was close (p=0.55). There were no neonatal deaths and no cases of brain damage (which was a result in the 2004 Landon et al study). In short, they found “no difference in major or minor maternal morbidity [between TOL and CS and] no serious neonatal morbidity.”
The number that is most important to me is the rate of uterine rupture because that is one of the reasons that anti-VBAC OBs give for not permitting women a trail of labor. The rate found in this study was 0.12% which is far lower than any other study has reported. They concluded, “with our well-defined protocol, a trial of labor after cesarean seems to be as safe for the mother and infant as planned cesarean delivery, and the hospital stay is shorter.”
In the US, is it highly unusual for an OB to permit a pregnant woman to wait until 42 weeks for spontaneous labor. Given how the accuracy of due dates can vary greatly depending on when a woman ovulated the month of conception (which is why charting is so important), I would hope that more doctors would permit women to gestate in peace longer rather than inducing or scheduling a repeat, or primary, CS.
Hopefully this research will prompt more studies to focus on the risks of waiting until 42 weeks for spontaneous labor vs. the risks of inductions at 42 weeks with AROM and/or small amounts of pitocin. This would challenge the current prevalent practice of automatically scheduling a repeat cesarean at 40 weeks or even earlier.
My ultimate wish is for doctors and hospitals to become more supportive of VBACs. In an ideal world, women would become their own health advocates and educate themselves on the advantages and risks of standard medical procedures and interventions commonly performed under the “standard of care” umbrella and start taking more responsibility for their medical care rather than abdicating all decision-making to their OB. Conventional wisdom states that OBs are ultra-conservative in their decision making due to malpractice concerns. However, if we as the public stopped looking to doctors as if they were gods, and thus expecting them to literally produce miracles, and started having more realistic expectations based on our own research and knowledge, maybe doctors would not feel such pressure and would permit women a TOL rather than routinely scheduling a cesarean.
Just as important is to interview OBs and midwives and find one whose birth philosophy best matches your own because there is not one way to practice medicine. Not all OBs are anti-VBAC or routinely require an IV, continuous fetal monitoring, and laboring in bed flat on your back or routinely perform episiotomies, AROMs, and inductions. It is an art just as it is a science and we have a choice who we hire to guide us through one of the most incredible moments of our lives.
Gonen, R., MD, Nisenblat, V., MD, Barak, S., MD, Tamir, A., DSc, and Ohel, G., MD. (2006). Results of a Well-Defined Protocol for a Trial of Labor After Prior Cesarean Delivery. Obstetrics & Gynecology, 107, 240-245.







Great study! Now the question is…will it make it into the media???
I will point out that 20 microunits per minute of Pit is a HIGH dose…so it is amazing that the rupture rate was still so low. The package insert for Pitocin says that 6 microunits per minute mimics spontaneous labor (so 20 microunits is 3.33 times as intense as natural labor!), and levels above 10 microunits per minute are “rarely needed.”
Good article. I wanted to mention, though, that the link to the study in the post is broken.
[...] а рискът от натална смърт или нараняване е 0.05% (Landon 2004, Gonen 2006, Cahill [...]
Thank you for the article. Would that be possible to get a working link to that study? I need to refer to it in my analysis.
So sorry for the broken link. ACOG did a complete overall of their journal’s website, so all the old links no longer work. I’m updating them as they are brought to my attention. Thank you!
[...] cut” cesarean is 0.2% – 0.4% and the risk of infant death or injury is 0.05%. (Landon 2004, Gonen 2006, Cahill [...]