Comparison of two labor induction regimens with intravaginal misoprostol 25 μg and adverse perinatal outcomes

TL;DR

This study compares two dosing schedules of a drug used to induce labor and finds that one schedule leads to better outcomes for mothers and babies.

Contribution

The study identifies optimal dosing intervals for misoprostol in labor induction and links them to reduced adverse outcomes.

Findings

Women using misoprostol every 4 hours had fewer tablets but more adverse outcomes compared to those using it every 6 hours.

Using misoprostol every 6 hours was associated with lower postpartum hemorrhage and better labor progression.

Factors like dosing interval, parity, and Bishop’s score predict successful labor induction.

Abstract

The aim of the study was to compare two labor induction regimens (4 and 6 h), to determine predictors of successful labor induction with intravaginal misoprostol 25 μg tablets, and to evaluate the association with adverse perinatal outcomes.

This was a retrospective cohort study that included singleton pregnancies undergoing induction of labor with an intravaginal misoprostol 25 μg tablet between 37 and 42 weeks of gestation. The pregnant women were divided into two groups: Group 1—intravaginal misoprostol 25 μg every 4 h and Group 2—intravaginal misoprostol 25 μg every 6 h.

Pregnant women were divided into Group 1 (n=289) and Group 2 (n=278). Group 1 had a higher median number of intravaginal misoprostol 25 μg tablets (3.0 vs. 2.0 tablets, p<0.001), a lower prevalence of postpartum hemorrhage (7.6 vs. 32.7%, p<0.001), and a higher need for oxytocin (odds ratio [OR]: 2.1, 95%CI: 1.47–2.98, p<0.001) than Group 2. Models including intravaginal misoprostol 25 μg tablets every 4 and 6 h [x2(1)=23.7, OR: 4.35, p<0.0001], parity [x2(3)=39.4, OR: 0.59, p=0.031], and Bishop’s score [x2(4)=10.8, OR: 0.77, p=0.019] were the best predictors of failure of labor induction. A statistically significant difference between groups was observed between the use of the first intravaginal misoprostol 25 μg tablet at the beginning (Breslow p<0.001) and the end of the active labor phase (Long Hank p=0.002).

Pregnant women who used intravaginal misoprostol 25 μg every 4 h had a longer time from the labor induction to the beginning of the active phase of labor and higher rates of adverse perinatal outcomes than women who used intravaginal misoprostol 25 μg every 6 h.

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