Is Vaginal Delivery After C-Section Safe?

Dec. 15, 2004 -- Having a vaginal delivery after a prior cesarean section is slightly riskier to both the mother and her baby than having a planned C-section.

It's an issue that's been debated for several years now. In fact, the numbers of vaginal births in women that have had prior cesarean deliveries has fallen steadily to 13% in 2002. Reports of uterine rupture because of vaginal delivery attempts in women with prior cesareans and their catastrophic consequences may have led to these declines.

A comprehensive study, published earlier this year, showed that almost 75% of women who attempted labor after a prior C-section had a successful vaginal delivery. The study showed that the complication rate was lower in these women than in those who had planned surgical deliveries. In a planned surgical (cesarean) delivery, women do not go into labor in order to deliver a baby.

The researchers estimated the risk for serious newborn complications was one in 2,000 deliveries when vaginal birth after C-section was attempted. Uterine rupture is the biggest concern with vaginal births after cesarean delivery (VBAC), but the complication occurred in less than 1% of women who took part in the study.

Vaginal Birth After C-Section or Planned C-Section?

The study, which appears in this week's New England Journal of Medicine, shows that VBAC carries a greater risk than planned C-sections -- but those risks are low, reports researcher Mark B. Langdon, MD, with the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

Langdon's study results "are, arguably, 'as good as they can get' in the United States," writes Michael F. Greene, MD, in an accompanying editorial. Greene is a professor of obstetrics and gynecology with Massachusetts General Hospital in Boston. The strength of large studies like Langdon's "is that they report 'real world' results," he adds.

Langdon's study involved women who had prior C-sections. There were 17,900 women who attempted a vaginal delivery after going into labor and 15,800 who had a planned cesarean delivery without labor.

In women who underwent a vaginal delivery after going in to labor:

• 0.7% women had uterine rupture.
• 1.7% needed blood transfusions versus 1% who had repeat C-sections.
• 3% had endometritis, an inflammation of the uterine lining that can put women at risk of death from septic shock, a rare occurrence. In women who had planned C-sections, 1.8% had endometritis.

These adverse events were "significantly more common" after a trial of labor than with a planned C-section, he writes. This was especially true when labor had been unsuccessful, he adds.

For infants, frequency of brain or nervous system damage or death was "significantly greater" for infants born via VBAC, reports Langdon. However, the risks were still small: Two infants with brain damage died during vaginal delivery.

Overall, his data indicates the risk of labor and a vaginal delivery after a prior C-section is small but greater than with planned C-section, Langdon writes. His hope is that the information will help women make the sometimes difficult choice between vaginal delivery and planned C-section.

SOURCES: Langdon, M. New England Journal of Medicine, Dec. 16, 2004; vol 351: pp 2581-2589. Greene, M. New England Journal of Medicine, Dec. 16, 2004; vol 351: pp 2647-2649. WebMD Medical News: "Vaginal Delivery After C-Section Mostly Safe."