Optimal Dose of Vaginal Misoprostol for Cervical Ripening before Hysteroscopy: A Randomized Double-Blind Study

Abstract Study Objective To evaluate the optimal dose of vaginal misoprostol (200 and 400 µg) for cervical priming before operative hysteroscopy. Design A randomized, controlled, double-blind trial (Canadian Task Force classification I). Setting A university hospital. Patients Sixty-eight patients undergoing operative hysteroscopy. Interventions Patients were randomized to receive a low (200 µg) or high (400 µg) dose of misoprostol administered vaginally 8 hours before operative hysteroscopy. Measurements and Main Results The primary outcome was perioperative dilatation time, and the secondary outcome measurements included the subjective difficulty of cervical dilatation assessed by the surgeon, operative time, self-reported adverse events after vaginal administration and before the start of the operation, and complications during the procedure. A comparison of the 200-µg (n = 34) and 400-µg (n = 34) misoprostol cohorts revealed similarities when comparing time with cervical dilatation, operative difficulty, result, and time. Misoprostol-related adverse events were significantly lower in the 200-µg cohort than the 400-µg cohort (58.8% vs 85.3%, p = .015). Abdominal pain was the most common adverse event and was higher in the 400-µg cohort compared with the 200-µg cohort (73.5% vs 50.0%, p = .046). However, there were no operative delays resulting from adverse events, and all individuals reported the procedure to be tolerable and recovered without medication or treatment. Conclusion Both 200 µg and 400 µg vaginally administered misoprostol are effective for cervical dilatation, and we recommend vaginal administration of 200 µg misoprostol for cervical dilatation 8 hours before operative hysteroscopy because of lower adverse events in the 200-µg group as well as similar efficacy between cohorts.