Intravaginal isonicotinic acid hydrazide (INH) versus misoprostol for cervical ripening prior to hysteroscopy

The aim of the present study was to compare the efficacy of vaginal isoniazid (isonicotinic acid hydrazide [INH]) and vaginal misoprostol in cervical ripening before hysteroscopic surgery.

This randomized controlled trial included patients scheduled for hysteroscopic surgery during April 2016 and June 2017. The inclusion criteria were as follows: postmenopausal women or those at premenopausal age who had not had a vaginal delivery and candidate for diagnostic or operative hysteroscopy with closed cervix before intervention. The INH group (intervention group) received 900 mg of vaginal isoniazid (three 300-mg pills) 6-8 hours before hysteroscopic surgery. The misoprostol group (control group) received 400 micrograms of vaginal misoprostol 6-8 hours before hysteroscopic surgery. Finally, the efficacy of the 2 agents was comparatively analyzed.

Baseline characteristics were comparable between the groups. In 67 cases in the INH group (95%) and 45 in the misoprostol group (50%), hysteroscopic entry was successful without additional mechanical dilation, and this difference was statistically significant (P=0.001). The odds ratio (OR) obtained in this study was 0.57 for both INH and misoprostol groups (OR, 0.57; 95% confidence interval, 0.43-0.75). Further, 19 cases in the INH group vs. 45 cases in the misoprostol group did not respond to the intervention, indicating statistically significance (P=0.001).

Vaginal INH is more effective than misoprostol in cervical ripening before hysteroscopic surgery and can be a good alternative to misoprostol.

Iranian Registry Clinical Trial (IRCT) Identifier: IRCT2015112821506N4.