291 Neonatal and maternal outcomes in laboring nulliparas by cesarean and operative vaginal delivery rates

Abstract

To evaluate the association between cesarean delivery (CD) rates and neonatal and maternal outcomes, and whether operative delivery (OVD) rate modifies this association. Secondary analysis of a randomized trial of labor induction versus expectant management in low-risk nulliparous participants with a vertex fetus. We excluded those delivered in hospitals with <100 participants. The centers were categorized into CD and OVD tertiles (low, medium and high) according to their CD and OVD rates in the trial participants. The primary outcome was a composite of adverse neonatal outcomes (defined in Figure); the secondary outcome was a maternal composite (defined in Table). Multivariable regression was used to estimate the association between CD tertiles and outcomes, as well as test for interaction between CD and OVD tertiles. Of 6,106 participants, 4,973 (81%) met inclusion criteria. The mean respective CD rates in the low, medium and high tertiles were 15.0%, 18.7% and 23.9%, and 5.0%, 7.5%, and 11.9% for OVD. The rates of OVD were similar across CD tertiles (8.1%,8.3%,8.0%). For the adverse neonatal composite, there was significant interaction between CD and OVD. If OVD was infrequent (lowest tertile), the adverse neonatal composite was more common in the mid- (aRR 2.87;95%CI 1.88,4.38) or high CD tertiles (aRR 2.93;95%CI 2.04, 4.22). Conversely, if OVD were frequent (highest tertile), the neonatal composite was less common in middle tertile CD group (aRR 0.78; 95%CI 0.62,0.99). The adverse maternal outcome composite was more frequent with a higher rate of CD (medium and high CD tertiles) compared with the lowest tertile (aRR 1.21;95%CI 1.05, 1.39, aRR 1.18;95% CI 1.03, 1.36 respectively, table and figure). Among low-risk nulliparous subjects, the frequency of CD did not vary by OVD rates. While adverse maternal outcomes were lowest in centers with lowest CD rates, the risk of the neonatal composite was lower in the medium CD group among those in the highest OVD tertile. Optimizing maternal and neonatal outcomes requires balancing CD and OVD rates.View Large Image Figure ViewerDownload Hi-res image Download (PPT)