691: Outcomes of elective induction of labor at 38 weeks versus expectant management until week 39

Abstract

Recent evidence suggests that elective induction of labor may reduce cesarean deliveries and other obstetric outcomes. This study analyzes differences in maternal and neonatal outcomes from elective induction of labor (eIOL) at 38 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=231,567). We compared outcomes from eIOL, defined by the Joint Commission, at 38 weeks against one additional week of expectant management and delivery at 39 weeks. Maternal outcomes of interest were cesarean delivery, operative vaginal delivery, 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. A p-value of less than 0.05 was used to indicate statistical significance. In our cohort of 231,567 deliveries, there were significant differences in the incidence of cesarean delivery, perineal tears, chorioamnionitis, and endomyometritis in women who were electively induced at 38 weeks compared to those who received expectant management and delivered at 39 weeks. However, the rate of operative vaginal delivery was not significantly different between the two groups. The rate of intrauterine fetal death was also significantly decreased when women were electively induced at 38 weeks. Logistic regression analysis indicated expectant management for one additional week, with delivery at 39 weeks, significantly increased cesarean deliveries (OR 1.45, 95% CI 1.37-1.54) but decreased RDS in neonates (OR 0.83, 95% CI 0.71- 0.98). There were no differences between the two groups for neonatal outcomes of hypoglycemia, HIE and jaundice. 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 expectant management for one additional week.