Repeat cesarean deliveries optimal at 39 weeks' gestation

In order to minimize adverse maternal and neonatal outcomes, ob/gyns should schedule repeat cesarean deliveries at 39 weeks’ gestation, say the results of a study presented at the 2012 annual meeting of the Society for Maternal-Fetal Medicine, The Pregnancy Meeting, in Dallas, Texas (Abstract 38; presented February 10, 2012).

The study, which was conducted for the Eunice Kennedy Shriver National Institute of Child Health and Human Development, included almost 24,000 women delivering via repeat cesarean. Among these women, 12% delivered at 37 weeks, 31% delivered at 38 weeks, 41% delivered at 39 weeks, 11% delivered at 40 weeks, and 5% delivered at 41 weeks. The authors compared the risks associated with elective repeat cesarean delivery at each gestational age and looked at cumulative maternal and neonatal risks associated with not delivering at each age.

Elective repeat cesarean deliveries scheduled after 37 or 38 weeks’ gestation were associated with significantly lower rates of composite adverse neonatal outcomes compared with deliveries at 37 and 38 weeks. In addition, adverse neonatal outcomes were significantly more frequent when pregnancies continued past 39 weeks compared   with delivery at 39 weeks.

Conversely, maternal outcomes were better when delivery was scheduled later than 37 or 38 weeks rather than at 37 or 38 weeks, but the difference only became significant at 37 weeks. Composite maternal outcomes were significantly worse for deliveries after 39 weeks rather than at 39 weeks.

Taking into consideration the welfare of both the mother and child, the authors concluded that optimal timing of repeat cesarean delivery is 39 weeks’ gestation, even after factoring in the risks associated with continuing pregnancy.

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