Association between timing of elective cesarean delivery and adverse outcomes among women with at least two previous cesareans

Timing of cesarean delivery in women with ≥2 previous cesarean deliveries

BACKGROUND

The rate of cesarean delivery is continuously increasing with the leading indication being a previous cesarean delivery. For women with 1 previous cesarean delivery, it is generally agreed that the optimal timing of delivery by elective cesarean delivery is during the 39th week of gestation, whereas for women with ≥2 previous cesarean deliveries, the optimal delivery time remains debatable.

OBJECTIVE

To assess the maternal and neonatal risks associated with elective delivery at different gestational ages ranging from 37 0/7 to 39 6/7 weeks' gestation and to compare it with expectant management among women with at least 2 previous cesarean deliveries.

STUDY DESIGN

This was a retrospective, population-based cohort study of all women with at least 2 previous cesarean deliveries who delivered after 36 6/7 weeks of gestation in Ontario, Canada, between April 2012 and March 2019. Women with multifetal pregnancies or major fetal anomalies were excluded. For each completed gestational week, outcomes of women who had an elective repeat cesarean delivery at that week solely because of 2 previous cesarean deliveries were compared with the outcomes of those who were managed expectantly and delivered at a later gestational age. The primary outcome was a composite of maternal outcomes including mortality and severe maternal morbidity. Secondary outcomes were adverse neonatal outcomes.

RESULTS

A total of 26,522 women met the inclusion criteria. The maternal risk was similar for elective delivery at 37 0/7 to 38 6/7 weeks of gestation compared with expectant management. However, elective delivery at 39 0/7 to 39 6/7 weeks' gestation was associated with a decreased risk for adverse outcomes when compared with expectant management (adjusted risk ratio, 0.51; 95% confidence interval, 0.29-0.91). For the neonate, elective delivery during the 37th week of gestation significantly increased the incidence of the composite adverse outcome than in an ongoing pregnancy (adjusted risk ratio, 1.68; 95% confidence interval, 1.39-2.01), but was comparable for elective delivery at 38 0/7 to 39 6/7 weeks' gestation and expectant management. The risk for an unplanned cesarean delivery increased from 6.5% before 38 weeks' gestation to 21.7% before 39 weeks' gestation and to 32.6% before 40 weeks' gestation.

CONCLUSION

For women with ≥2 cesarean deliveries, elective delivery at 38 0/7 to 38 6/7 weeks' gestation likely represents the optimal balance between neonatal and maternal risk while decreasing the likelihood of an unplanned cesarean delivery.