Cervical Priming by Vaginal or Oral Misoprostol Before Operative Hysteroscopy: A Double-Blind, Randomized Controlled Trial

Study objective: To evaluate whether misoprostol oral is as effective as vaginal tablets for cervical ripening.

Design: Randomized controlled trial involving a parallel, double-blinded study (Canadian Task Force Classification IB).

Setting: Department of Obstetrics and Gynecology, Cairo University Hospital, between January 2014 and January 2016.

Patients: Patients undergoing operative hysteroscopy for various indications.

Interventions: At 12 hours before hysteroscopy, the oral group received a 400-μg misoprostol tablet and 2 vaginal starch tablets. The vaginal group received 400 μg of misoprostol and 2 oral starch tablets. The control group received 2 oral starch and 2 vaginal starch tablets as placebo. Preoperative preparation was the same in all patients.

Measurements and main results: The main outcome measures were width of the endocervical canal, ease of dilatation, time to dilatation, and adverse effects. All subjects eligible for operative hysteroscopy (n = 430) were invited to participate. Twenty subjects refused, and 20 subjects were excluded. The enrolled subjects (n = 390) were randomized to oral misoprostol, vaginal misoprostol, or placebo. The differences in mean width of the endocervical canal between the oral and the control groups (4.79 ± 1.07 mm vs 3.92 ± 0.92 mm), and also between the vaginal and the control groups (4.25 ± 0.71 mm vs 3.92 ± 0.92 mm) were significant (p < .001 for both). Moreover, the difference in mean width of the endocervical canal between the oral and the vaginal groups was significant (4.79 ± 1.07 mm vs 4.25 ± 0.71 mm; p = .009). Cervical entry was easier in the oral and vaginal groups compared with the control group (mean Likert score, 4.25 ± 0.64 vs 4.22 ± 0.74 vs 2.55 ± 0.87; p < .001). In addition, the ease of cervical entry did not differ significantly between the oral and vaginal groups (p = .998). The mean time to dilatation was shorter in the oral group and the vaginal group (compared with the control group (48.98 ± 12.6 seconds vs 46.55 ± 15.32 seconds vs 178.05 ± 74.18 seconds; p < .001), but the difference between the oral and vaginal groups was not significant (p = .987). Adverse effects were comparable between groups (p > .05).

Conclusion: We found no statistically significant difference in the efficacy of cervical priming between oral misoprostol and vaginal misoprostol.