Maternal Morbidity in the Second Stage of Labor: Analysis to Simulate the Clinical Choice

Abstract

Objective: To analyze maternal morbidity in the second stage of labor in a manner that approximates clinical choice. Study Design: Secondary analysis of the Consortium for Safe Labor, which included 228,688 deliveries at 19 hospitals between 2002 and 2008. We included the 107,675 women who were undergoing a trial of labor without a prior uterine scar or history of substance abuse, who reached the second stage, with a liveborn, non-anomalous, vertex, singleton, at term of at least 2500 grams. Maternal complications included postpartum fever, hemorrhage, blood transfusion, thrombosis, ICU admission, hysterectomy and death. For maternal complications, we simulated the clinical choice by comparing operative vaginal or cesarean deliveries to continued expectant management at every hour in the second stage. For neonatal complications, we modeled the risk of severe neonatal complication by second stage duration for spontaneous vaginal deliveries only, adjusting for maternal demographics, co-morbidities, and delivery hospital. Severe neonatal complications included death, asphyxia, hypoxic-ischemic encephalopathy (HIE), seizure, sepsis with prolonged stay, need for mechanical ventilation, and 5-minute Apgar score < 4. Results: Maternal morbidity was higher with operative vaginal/cesarean delivery vs. continued expectant management for every hour in the second stage, a difference that was statistically significant at hour 2 (18.4% vs 14.7%; p<0.01). Overall, 951 (0.88%) of deliveries were complicated by a severe neonatal complication. A second stage over 4 hours was associated with an adjusted odds of severe neonatal complication of 2.10 (95% CI 1.32-3.34) as compared to women who delivered in the first hour. Conclusion: There is a trade-off between maternal and neonatal morbidity in the second stage of labor. Serious neonatal complications rise throughout, however, there is no time at which maternal morbidity is improved with a cesarean or operative vaginal delivery. Strategies are needed to identify neonates at highest risk of complication for targeted intervention.