Determining the Optimal Time Interval between Vaginal Dinoprostone Administration and Diagnostic Office Hysteroscopy in Nulliparous Women: A Randomized, Double-blind Trial.

Study objective: To determine the optimal timing of vaginal dinoprostone administration before office hysteroscopy (OH) in nulliparous women.

Design: Randomized, double-blind trial. Setting: Tertiary referral hospital. Patients: A total of 180 nulliparous women undergoing diagnostic OH. Interventions: We randomly allocated the women to long-interval or short-interval dinoprostone groups: three mg dinoprostone was administered vaginally 12 hours before OH in the long-interval group and 3 hours before OH in the short-interval group. Measurements and main

Results: The primary outcome was pain during OH measured using a 100-mm visual analog scale (0 = no pain; 100 = worst pain imaginable). The secondary outcomes were ease of hysteroscope passage, patient satisfaction score, and drug-related adverse effects. The patients in the long-interval dinoprostone group had lower pain scores during OH (p <.001). Contrarily, pain scores 30 minutes after the procedure were similar in both groups (p = .1). The patient satisfaction score was higher and clinicians found hysteroscope passage through the cervical canal easier and quicker in the long-interval dinoprostone group than in the short-interval group (p <.001, p = .003, and p <.001, respectively). Side effects were comparable in both study groups.

Conclusion: Vaginal dinoprostone administered 12 hours before OH was more effective than that administered 3 hours before OH in reducing pain during OH in nulliparous women, with easier hysteroscope insertion, shorter procedure duration, and higher patient satisfaction score.