538: Outcomes of elective induction of labor at 39 weeks versus expectant management until week 40

Abstract

This study analyzes differences in maternal and neonatal outcomes from elective induction of labor (eIOL) at 39 weeks versus one additional week of expectant management in nulliparous women at community hospitals. We conducted a retrospective cohort study of singleton, vertex, nonanomalous deliveries in community hospitals in California between 2007 and 2011 using linked hospital discharge and vital statistics data (n=252,107). We compared outcomes from eIOL, defined by the Joint Commission, at 39 weeks against one additional week of expectant management and delivery at 40 weeks. The maternal outcomes of interest were cesarean delivery, operative vaginal delivery, maternal blood transfusion, perineal tear, chorioamnionitis, and endomyometritis. Neonatal outcomes of interest were intrauterine fetal death, 5 minute Apgar less than 7, NICU admission, respiratory distress syndrome (RDS), hypoglycemia, hypoxic ischemic encephalopathy (HIE) and jaundice. Results were compared using chi square analysis and examined using multivariate logistic regression controlling for maternal age, comorbidities, ethnicity, education level, initiation of prenatal care in the first trimester, and insurance status. A p-value of less than 0.05 was used to indicate statistical significance. In our cohort of 252,107 deliveries, there were significant differences in the incidence of cesarean delivery, operative vaginal delivery, maternal transfusion, perineal tear, chorioamnionitis, endomyometritis in women who were electively induced at 39 weeks compared to those who received expectant management and delivered at 40 weeks. Rates of adverse neonatal outcomes of intrauterine fetal death and hypoglycemia were also significantly decreased when women were electively induced at 39 weeks. However, RDS, HIE and jaundice were not significantly different between the two groups. Logistic regression analysis indicated expectant management until 40 weeks significantly increased cesarean deliveries (OR 1.37, 95% CI 1.32-1.42) and operative vaginal deliveries (OR 1.0, 95% CI 1.02-1.15). The maternal and neonatal outcomes following birth are associated with the timing and management prior to delivery. These findings can be used to counsel women regarding the risks of maternal and neonatal complications from elective induction of labor and one additional week of expectant management.