891 Use of misoprostol for labor induction among women with fetal growth restriction

Abstract

To determine whether vaginal misoprostol use among women with fetal growth restriction (FGR) for induction of labor (IOL) was associated with cesarean delivery (CD) or neonatal morbidity. This was a secondary analysis of a prospective cohort study of women undergoing IOL at one institution from July 2017-July 2019. Women were included if they were undergoing IOL at ≥37 weeks with intact membranes and an unfavorable cervix (Bishop score of ≤6 and cervical dilation ≤2cm). Women with a prior CD or estimated fetal weight (EFW)<3rd percentile with abnormal umbilical artery dopplers were excluded. FGR was defined as EFW <10th percentile. Our exposed group was those who received any misoprostol during IOL (alone or in combination with cervical Foley); unexposed were those who did not receive misoprostol. Choice of induction agents were at provider discretion. There were 1,610 women in the entire cohort; 419 had known FGR and were included. There was no difference in CD risk among those who received misoprostol versus those who did not (25.3% vs 22.9% p=0.72), even when controlling for confounders including parity, bishop score, and body mass index, (aOR 0.75, 95% CI 0.34-1.67). Among all CDs, the rate of CD for non-reassuring fetal heart tones (NRFHT) was also not significantly different between groups (misoprostol 56% vs no misoprostol 55%, p=0.91). Notably, the rate of neonatal 5 minute Apgar score <7 was lower among those who received misoprostol compared to those who did not (1.3% vs. 6.2%, p=0.02). Neonatal intensive care unit admission >48 hours was also lower among those who received misoprostol, though this did not reach statistical significance (3.2% vs 6.2%, p=0.13). When restricted to those with FGR<5th percentile, results were unchanged. In this large prospective cohort of women with FGR undergoing term IOL, misoprostol exposure did not increase CD risk overall, CD for NRFHT, or neonatal morbidity. These findings provide reassurance that misoprostol can be used safely for cervical ripening in women with FGR.