Comparison of labor induction with titrated oral misoprostol solution between nulliparous and multiparous women

Abstract

Aim: To compare the outcomes of labor induction with oral misoprostol solution between nulliparous and multiparous women. Methods: We retrospectively reviewed the medical records of all patients between 37 and 42 weeks of gestation with a Bishop score ≤6 who underwent labor induction with titrated oral misoprostol solution. The women were allocated into two groups: nulliparous and multiparous. The women received one basal unit of misoprostol solution (20 mL, 1 μg/mL) every hour for four doses; additional doses were titrated against individual uterine response. The interval of latent and active phase and vaginal delivery within 12 h were the primary outcomes. Results: Of the 112 women included in the study, 49 (43.8%) mulliparae and 63 (56.2%) multiparae underwent labor induction with titrated oral misoprostol solution. Complete vaginal delivery occurred within 12 h in 21 (42.9%) nulliparae and 54 (85.7%) multiparae (RR, 0.54; 95% CI, 0.39-0.76). All induction intervals, including the latent and active phases, were significantly shorter in the multiparous group (P < 0.01). Induction failure did not occur in any patient in either of the groups. There were no instances of hyperstimulation, which was defined as tachysystole or hypertonus with nonreassuring fetal heart rate pattern, although tachysystole, defined as the presence of at least six contractions in 10 min over at least two 10-min windows, occurred in four (8.2%) nulliparous women and in four (6.3%) multiparous women. Hypertonus, defined as a single contraction lasting more than 2 min, did not occur in either group. None of the neonates in either group had an Apgar score of <7 at 1 min. Conclusion: Titrated oral misoprostol solution is a promising method of labor induction for both nulliparous and multiparous women. © 2010 Japan Society of Obstetrics and Gynecology.