Objective: To compare maternal and neonatal outcomes when primary cesarean delivery is performed in the second stage of labor compared with the first stage.
Methods: Between January 1, 1999, and December 31, 2000, a prospective observational study of primary cesarean deliveries was conducted at 13 university centers comprising the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. The primary outcomes of interest included a maternal composite (composed of at least one of the following: endometritis, intraoperative surgical complication, blood transfusion, or wound complication) and neonatal composite (which included at least one of the following: Apgar score of 3 or less at 5 minutes, neonatal death, neonatal intensive care unit admission, seizure, delivery room intubation in the absence of meconium, or fetal injury).
Results: A total of 11,981 cesarean deliveries were available for analysis: 9,265 were performed in the first stage and 2,716 in the second stage. Cesarean deliveries performed in the second stage were associated with longer operative times, epidural analgesia, chorioamnionitis, and higher birth weight (all P<.001). The maternal composite index was slightly increased in women undergoing cesarean delivery in the second stage of labor, primarily due to uterine atony, uterine incision extension, and incidental cystotomy. This difference was significant after multivariable analysis (odds ratio 1.21, 95% confidence interval 1.07-1.37). After multivariable analysis, the neonatal composite did not differ significantly between groups (odds ratio 0.96, 95% confidence interval 0.84-1.08).
Conclusion: Cesarean delivery in the second stage of labor is associated with slightly increased maternal but not neonatal composite morbidity.
Level of evidence: II.