Intravaginal Misoprostol for Cervical Ripening and Labor Induction in Nulliparous Women: A Double-blinded, Prospective Randomized Controlled Study / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>In China, no multicenter double-blinded prospective randomized controlled study on labor induction has been conducted till now. This study is to evaluate the efficacy and safety of intravaginal accurate 25-μg misoprostol tablets for cervical ripening and labor induction in term pregnancy in nulliparous women.</p><p><b>METHODS</b>This was a double-blinded, prospective randomized controlled study including nulliparous women from 6 university hospitals across China. Subjects were randomized into misoprostol or placebo group with the sample size ratio set to 72. Intravaginal 25-μg misoprostol or placebo was applied at an interval of 4 h (repeated up to 3 times) for labor induction. Primary outcome measures were the incidence of cumulative Bishop score increases ≥3 within 12 h or vaginal delivery within 24 h. Safety assessments included the incidences of maternal morbidity and adverse fetal/neonatal outcomes.</p><p><b>RESULTS</b>A total of 173 women for misoprostol group and 49 women for placebo were analyzed. The incidence of cumulative Bishop score increases ≥3 within 12 h or vaginal delivery within 24 h was higher in the misoprostol group than in the placebo (64.2% vs. 22.5%, relative risk [RR] 2.9, 95% confidence interval [CI] 1.4-6.0). The incidence of onset of labor within 24 h was significantly higher in the misoprostol group than in the placebo group (48.0% vs. 18.4%, RR 2.6, 95% CI 1.2-5.7); and the induction-onset of labor interval was significantly shorter in the misoprostol group (P = 0.0003). However, there were no significant differences in the median process time of vaginal labor (6.4 vs. 6.8 h; P = 0.695), incidence (39.3% vs. 49.0%, RR 0.8, 95% CI 0.4-1.5) and indications (P = 0.683) of cesarean section deliveries, and frequencies of maternal, fetal/neonatal adverse events between the groups.</p><p><b>CONCLUSION</b>Intravaginal misoprostol 25 μg every 4 h is efficacious and safe in labor induction and cervical ripening.</p>