Evening Primrose Oil Effect on the Ease of Cervical Ripening and Dilatation Before Operative Hysteroscopy

Background: Some important complications such as cervical tears, creation of false tract and uterine perforation may happen during cervical entry of operative hysteroscope. These complications can be reduced by priming agents. Objectives: The current study aimed to determine the effect of vaginal evening primrose oil (EPO) on cervical ripening and dilatation before operative hysteroscopy. Patients and Methods: Thirty-six non-menopausal patients without a history of normal vaginal delivery and fourteen menopausal patients who underwent operative hysteroscopy were selected for the study. By simple randomization method, twenty-eight females received two soft gels of EPO (each 500 mg) and twenty-two females received placebo; in both cases the soft gels were applied to the posterior vaginal fornix 6 - 8 hours before operative hysteroscopy. Results: The primary outcome measures were the total dilatation time starting with Hegar size "3 to end point of 10 mm" as well as the size of the first dilator used to apply force. The secondary outcomes were uterine cervico-vaginal complications and also adverse effects related to the use of vaginal EPO. The total cervical dilatation time was shorter among the subjects who received EPO than the ones who received placebo (Median: 33.5 second (26.25 - 41.5) vs. 75 second (30 - 127.5) P = 0.003). Also the first Hegar size that could be used to apply force for cervical dilatation was greater in size in the EPO group compared to those of the placebo group (Median: 8 mm (8 - 9) vs. 7 mm (5.75 - 8.25) P = 0.002). There were no uterine cervico-vaginal complications or adverse effects in the groups. Conclusions: EPO is effective to ripen the cervix before hysteroscopy. It is easy to use, available, inexpensive, and has no serious adverse effects.