Women's Health

Success rates for vaginal births after cesareans differ depending on whether the mother has certain conditions

Published success rates range from 60 to 80 percent for women who want to attempt to deliver a baby vaginally after a cesarean birth. However, a new study found actual success rates varied from 10 to 73.8 percent depending on whether certain maternal, fetal, or placental conditions were present. For example, women whose babies' heads were not in optimal position for a vaginal delivery had a success rate of only 9.8 percent when they attempted a vaginal birth after cesarean (VBAC), while women who had a history of herpes had a 71 percent success rate, those with mental conditions had a 71.7 percent success rate, and those with no conditions had a 73.8 percent success rate.

Kimberly D. Gregory, M.D., M.P.H., of Cedars Sinai Medical Center, and colleagues examined birth and discharge records from the California Office of Statewide Health Planning and Development from 2002. Of 41,450 women who attempted VBAC, they identified 12,324 who had high-risk clinical conditions. Rates for complications for mother and child ranged from 1 to 2 percent (except for maternal infection, which was 4.77 percent and neonatal respiratory conditions, which were 5.39 percent).

Complication rates were higher for mother and baby when high-risk conditions were present. For example, when a baby's head was not in the correct position for delivery, the odds that the mother would experience a uterine rupture was 8.8 times greater than a woman whose baby's head was positioned correctly. These findings indicate that VBAC is not an option for every woman, the authors suggest. Although many women are able to successfully complete a VBAC, women who have high-risk conditions may experience complications either for themselves or their children in attempting VBAC.

While additional research is needed to determine specific risk factors, providing this information to women can assist them in making informed choices about their deliveries. This study was funded in part by the Agency for Healthcare Research and Quality (HS11334).

See "Vaginal birth after cesarean: Clinical risk factors associated with adverse outcome," by Dr. Gregory, Lisa M. Korst, M.D., Ph.D., Moshe Fridman, Ph.D., and others in the April 2008 American Journal of Obstetrics and Gynecology 198(4), pp. 452.e1-452.e12.

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