Research Activities #251, July 2001

of Washington have found that women with a prior cesarean section who undergo labor for their second child are at increased risk for rupture of the uterus compared with women who elect to have another c-section. Uterine rupture is an uncommon but serious obstetrical condition that may result in hysterectomy, urologic injury, or a need for blood transfusion for the mother and neurologic impairment in the infant. Each year in the United States, approximately 60 percent of women with a prior cesarean delivery elect to have a trial of labor in a subsequent pregnancy. The researchers analyzed the records of more than 20,000 women who had their first child delivered by c-section in Washington State from 1987 through 1996 and also delivered a second child either by cesarean or following labor during the same time period. They found that a total of 91 women had a uterine rupture during the second birth. Women with a spontaneous onset of labor were 3.3 times more likely to have a uterine rupture than women who had a repeat csection without labor. Uterine rupture was highest when prostaglandin—a naturally occurring substance in the body that is sometimes used to induce labor—was used for the second birth. Compared with women who had repeat c-sections without labor, women who were induced without prostaglandin were nearly five times more likely to have a uterine rupture, and women with prostaglandin induction were 15 times more likely to have uterine rupture. The study was led by Mona Lydon-Rochelle, Ph.D., and supported by the Agency for Healthcare Research and Quality (National Research Service Award T32 HS00034) and the National Institute of Nursing Research at the National Institutes of Health. For more information, see “Risk of uterine rupture during labor among women with a prior cesarean delivery,” by Dr. LydonRochelle, Victoria L. Holt, Ph.D., Thomas R. Easterling, M.D., and Diane P. Martin, Ph.D., in the July 5, 2001 New England Journal of Medicine 345(1), pp. 3-8. ■ Research Activities