Maternal and Fetal Outcomes in Low-Risk Births After Induction of Labor Policy Change [ID 1355]

INTRODUCTION: An institutional policy change post-ARRIVE trial expanded induction of labor (IOL) after 39 weeks. This study aimed to assess the effect of this policy change on the rate of unplanned cesarean deliveries (CDs) among low-risk nulliparous women. METHODS: This is a retrospective cohort study of low-risk nulliparous deliveries after 39 weeks pre-policy change (2019) and post-policy change (2022). The primary outcome was the rate of unscheduled CD at 39 weeks or later. Secondary outcomes included maternal and neonatal adverse events, admission indication, CD indication, and the length of inpatient labor course and hospitalization. RESULTS: A total of 1,755 deliveries were included, with 975 in the 2019 cohort and 780 in the 2022 cohort. The 2022 cohort had a higher percentage of body mass index greater than 30 kg/m 2 (52.8% versus 61.4%, P =.01); groups were otherwise similar. The primary outcome of unplanned CD occurred in 26.8% of mothers in both cohorts ( P =.99). The rate of IOL was higher in the 2022 cohort (38% versus 52%, relative risk 1.37, P =.001). Indication for CD of non-reassuring fetal status was lower in the 2022 cohort (39% versus 26%, P =.005). Inpatient labor course greater than 24 hours was more common in the 2022 cohort (11.7% versus 20.3%, P =.001). CONCLUSIONS/IMPLICATIONS: The IOL policy change resulted in a higher rate of IOL and longer intrapartum time but did not affect the rate of unplanned CD or other maternal and neonatal adverse events in nulliparous, low-risk births at a single tertiary care institution.