Outcomes in Low-Risk Patients Before and After an Institutional Policy Offering 39-Week Elective Inductions [ID: 1379269

Abstract

INTRODUCTION: We aimed to pragmatically analyze the effect of offering elective induction of labor (eIOL) in low-risk patients on perinatal outcomes. METHODS: This was a retrospective cohort study of low-risk nulliparous or multiparous patients delivering live, nonanomalous singletons at a single center at greater than or equal to 39 0/7 weeks’ gestational age (GA). Those with prior or planned cesarean delivery (CD), ruptured membranes, medical comorbidities, or contraindications to vaginal delivery were excluded. Patients were categorized as before (pre-eIOL; January 2012 to March 2014) or after (post-eIOL; March 2019 to December 2021) an institution-wide policy offering eIOL at 39 0/7 weeks. Births from April 2014 to December 2018 were considered to be during-eIOL given increased exposure to eIOL during the period of the ARRIVE trial at our center. The primary outcome was CD. Characteristics and outcomes were compared between the pre- and during-eIOL, and pre- and post-eIOL groups, and adjusted OR (aOR) (95% CI) was calculated using multivariable regression. Subgroup analysis by parity was planned. RESULTS: Of 10,966 patients analyzed, 2,611 (23.8%) were pre-eIOL, 5,486 (50.0%) during-eIOL, and 2,869 (26.2%) post-eIOL. Groups differed with respect to labor type, age, race and ethnicity, marital and payor status, and GA at care entry. Post-eIOL was associated with lower odds of CD compared to pre-eIOL (aOR 0.75 [95% CI 0.66–0.87]), which was consistent for both nulliparas (aOR 0.71 [0.59–0.85]) and multiparas (aOR 0.64 [0.52–0.79]). During-eIOL was also associated with lower odds of CD compared to pre-eIOL (aOR 0.73 [0.65–0.82]). Both during- and post-eIOL groups were associated with higher odds of chorioamnionitis, operative delivery, and hemorrhage compared to pre-eIOL. However, only among post-eIOL were there fewer neonatal birth weights greater than 4,000 g, large-for-GA infants, and hypoglycemia compared to pre-IOL. CONCLUSION: Institutional policy offering eIOL at 39 0/7 to low-risk patients was associated with a lower CD rate and lower birth weights, and an increased risk of chorioamnionitis and hemorrhage.