LAS VEGAS — Using 400 mcg vaginal misoprostol 12–24 hours before hysteroscopy reduces the pain related to the procedure and the maximum peak force needed for dilatation of the cervix, results from a double-blind randomized trial demonstrated.
While the off-label use of vaginal misoprostol has been widely used to make the dilatation of the cervix easier, “most studies have measured the effects on the cervix by the largest Hegar dilator that could be inserted without resistance, which is a subjective measure,” Dr. Guy Waddell said in an interview after his poster presentation at the annual meeting of the AAGL. “The quality of these studies therefore is underrated. Moreover, the pain reported by the patient was rarely assessed,” said Dr. Waddell, a gynecologist at the University of Sherbrooke (Que.).
He and his associates used a cervical tonometer to objectively measure the force needed to dilate the cervix after priming with vaginal misoprostol, compared with placebo, in 101 women undergoing diagnostic hysteroscopy. The researchers also used the Visual Analog Scale to assess pain after dilatation to 6 mm.
Of the 101 women, 50 self-administered 400 mcg vaginal misoprostol while 51 self-administered vaginal placebo 12–24 hours before hysteroscopy. Their mean age was 51 years and their mean parity was 2.2. Complete data were missing on nine patients in the misoprostol group and two in the placebo group.
Dr. Waddell and his associates reported that the mean pain score after dilatation to 6 mm was 42.1 in the misoprostol group, compared with 57.2 in the placebo group, a difference that was statistically significant. The difference between groups retained significance after the researchers adjusted for baseline pain scores measured before randomization and any intervention (43.2 vs. 55.5, respectively). The force needed to dilate the cervix at 6 mm also was significantly less in the misoprostol group than in the placebo group (5.0 newtons vs. 7.5 newtons, respectively). There were no significant differences in the force needed to dilate the cervix at 3 mm (1.7 vs. 1.8 newtons), 4 mm (2.6 vs. 3.0 newtons), or 5 mm (4.3 vs. 4.0 newtons).
The number of side effects and complications were few, but pelvic cramping was reported significantly more often in the misoprostol group than in the placebo group.
“The demonstration that the cervix is more easily dilated with misoprostol at 6 mm suggests that, for any procedure needing the insertion of a device of more than 5 mm into the endometrial cavity, priming would be facilitating and could reduce the risk of complications,” the researchers wrote.
Dr. Waddell said he had no conflicts of interest to disclose.
Mean pain score after dilatation to 6 mm was 42.1 in the misoprostol group, compared with 57.2 in the placebo group. DR. WADDELL