Prior Vaginal Birth Decreases the Risk for Uterine Rupture in VBAC

Here's an entry in the no-duh Olympics.  You would think this didn't need to be pointed out, but sadly, to some folks it does.

Most caregivers know that once a woman has had a VBAC, she is at decreased risk for rupture  (the scar coming apart) in any future pregnancies.

The risk is never zero, mind.....once a cesarean, always a risk to some degree, whether you choose VBAC or repeat cesarean, which is why it's important to avoid that first cesarean whenever possible.....but a prior vaginal birth (either before or after the cesarean) does seem to lessen the risk for rupture.

However, once in a while, we in ICAN (the International Cesarean Awareness Network) hear about some ignorant caregiver telling women that they can only have one VBAC and then must have all repeat cesareans, or that the risk for rupture remains just as high each time, even after you've already had a VBAC. Wrong!

For all the Homer Simpson caregivers out there who need a primer on this topic, here's a research review that clearly shows that the risk for uterine rupture is significantly decreased in women who have had a prior vaginal birth.  D'oh!

This is another reason why it is so important to prevent cesareans whenever possible.  A vaginal birth is protective against so many complications, including one of the most serious, uterine rupture.  Even if a cesarean becomes truly necessary in a particular pregnancy, it is strongly to everyone's advantage if the woman has had a vaginal birth first, or if she has a vaginal birth (VBAC) afterwards. In most cases, it is more risky to expose them to successive cesareans, particularly multiple repeat cesareans.

Yet research shows the primary cesarean rate rising, and the VBAC rate dropping.

Graph from U.S. National Center for Health Statistics

Don't get me wrong.  I don't hate cesareans. It is wonderful to have life-saving technology and surgery available when truly needed, and there certainly are cases where a cesarean makes more sense. But don't underestimate the power of nature.

On a population-wide basis, vaginal birth offers the most benefits to most mothers and babies. We evolved to give birth vaginally, and we circumvent that casually at our peril.

This research points out yet again that it is to most birthing women's advantage to have a vaginal birth in their history. Most of the time, unnecessary primary cesareans and routine repeat cesareans should be avoided if possible.


Reference

Arch Gynecol Obstet. 2011 Nov;284(5):1053-8. Risk of uterine rupture in women undergoing trial of labour with a history of both a caesarean section and a vaginal delivery. de Lau H, et al. PMID: 21879334

PURPOSE: To determine the risk of uterine rupture for women undergoing trial of labour (TOL) with both a prior caesarean section (CS) and a vaginal delivery.

METHODS: A systematic literature search was performed using keywords for CS and uterine rupture. The results were critically appraised and the data from relevant and valid articles were extracted. Odds ratios were calculated and a pooled estimate was determined using the Mantel-Haenszel method.

RESULTS: Five studies were used for final analysis. Three studies showed a significant risk reduction for women with both a previous CS and a prior vaginal delivery (PVD) compared to women with a previous CS only, and two studies showed a trend towards risk reduction. The absolute risk of uterine rupture with a prior vaginal delivery varied from 0.17 to 0.46%. The overall odds ratio for PVD was 0.39 (95% CI 0.29-0.52, P less than 0.00001).

CONCLUSION: Women with a history of both a CS and vaginal delivery are at decreased risk of uterine rupture when undergoing TOL compared with women who have only had a CS.