Timing of vaginal misoprostol administration for cervical priming among women undergoing vaginoscopic hysteroscopy: a randomized controlled trial

Objective: To compare the ease of cervical entry after administration of vaginal misoprostol at 2 different intervals before vaginoscopic hysteroscopy. Methods: In this randomized, double-blinded study, 140 women undergoing vaginoscopic hysteroscopy were allocated into two groups: 1) short-interval: placebo tablet administered vaginally 12 hours before the procedure, followed by 200 mcg vaginal misoprostol 3 hours before, and 2) long-interval: 200 mcg vaginal misoprostol 12 hours before the procedure and a placebo tablet 3 hours before. The primary outcome was the ease of cervical entry, evaluated using a 5-point Likert scale, and the secondary outcomes included 1) time interval to cervical entry and completion of the procedure, 2) pain assessment using a visual analog scale (VAS), and 3) any adverse effects associated with the drug or procedure. Results: All except two patients with cervical stenosis underwent vaginoscopic hysteroscopy. The proportion of patients who reported "easy" or "very-easy" cervical entry was similar in both groups (64.3% [95% confidence interval [CI], 53.1-75.5%], vs. 72.9% [95% CI, 62.4-83.3%]; P=0.275). Pain perception was lower in the long-interval group than in the short-interval group (P=0.024). However, the temporal change in the pain score was not significantly different between the groups. The side effects of misoprostol were mild, self-limiting, and similar in both groups. Conclusion: Vaginal misoprostol administration 12 hours before vaginoscopic hysteroscopy was associated with a similar ease of entry but a lower perception of pain using the VAS than misoprostol administration 3 hours before the procedure.