(273) Use of prostaglandins for labor induction in pregnancies complicated by fetal growth restriction

Objective:
Practice patterns for induction of labor (IOL) in pregnancies affected by fetal growth restriction (FGR) often vary by provider due to a lack of evidence-based guidelines and concerns regarding labor intolerance with prostaglandin (PG) use. Prior studies are limited by restrictive exclusion criteria and omission of key confounding variables. We aimed to evaluate whether PG use during IOL in FGR pregnancies is associated with cesarean delivery (CD).

Study Design:
This retrospective cohort study included singleton pregnancies complicated by FGR undergoing IOL between January 2021 and December 2023 at a single tertiary care center. FGR was defined as an estimated fetal weight (EFW) or abdominal circumference < 10th percentile on the most recent ultrasound (US). Exclusion criteria included multiple gestation, delivery < 23 weeks, planned CD, and contraindications to PG use. Maternal demographics, IOL characteristics (including modified Bishop scores [BS]), US findings, and delivery outcomes were abstracted. Categorical variables were compared using chi-square tests and continuous variables with t-tests; linear and logistic regression were used to control for confounding variables.

Results:
Of 1,230 pregnancies, 312 met inclusion criteria (168 received PG; 144 did not). PG use was more common in nulliparous patients and those with BS ≤5 (Table). PG use was not associated with higher CD rates (20.1% vs. 22.6%, p=0.595); this finding persisted after excluding favorable BS and adjusting for parity (OR 0.98, 95% CI 0.52–1.83). CD rates did not differ by BS, parity, severity of FGR, or umbilical artery Dopplers. The primary CD indication of non-reassuring fetal heart rate was similar between groups (18.4% vs. 13.8%, p=0.612). PG use was associated with a modest, non-significant increase in labor duration (19.8 vs. 17.1 hours, p=0.067), which attenuated after adjusting for parity (p=0.239).

Conclusion:
PG use in IOL for pregnancies complicated by FGR was not associated with increased rates of CD. These findings support the use of PG for cervical ripening in pregnancies affected by FGR.