Objective: To assess the ability of a controlled-release misoprostol vaginal insert to induce labor using dose reservoirs of 25, 50, 100, and 200 microg.
Methods: This double-blind, dose ranging, randomized study was carried out in parous women requiring induction of labor at term. Each woman was randomly assigned to receive a single misoprostol vaginal insert that could remain in place for up to 24 hours and was removed for onset of active labor, an adverse event, or having reached 24 hours in situ. The primary outcome measure was time from insertion of the misoprostol vaginal insert to vaginal delivery of the neonate.
Results: A total of 124 women participated in the study. The median time to vaginal delivery was 27.5, 19.1, 13.1, and 10.6 hours for the 25-, 50-, 100-, and 200-microg doses, respectively. The percentage of women who delivered vaginally within 12 hours was 9%, 14%, 47%, and 53% (P<.001 using the 25-microg group as the comparator) and within 24 hours was 42%, 79%, 81%, and 70% (P=.003). Uterine hyperstimulation syndrome occurred in one woman who received the 25-mug, two women who received the 100-microg, and three women who received the 200-microg dose reservoirs.
Conclusion: Misoprostol vaginal inserts effectively induced labor in pregnant parous women at term.
Level of evidence: I.
Trial registration: ClinicalTrials.gov NCT00346840.