The primary outcome measure in this study was the preoperative cervical width after misoprostol administration. The secondary outcomes were duration of cervical dilatation, up to Hegar number 10, complications during cervical dilation and the hysteroscopy, and misoprostol associated side effects. The cervical width was assessed by performing cervical dilatation, starting with a number 10 Hegar dilator and subsequently inserting smaller Hegar dilatators until the dilator could pass through the internal os without resistance. The largest one that could be passed was recorded as the initial cervical width.
The mean cervical diameter, after oral and vaginal misoprostol of 400 μg, has been reported to be 6.0 ± 1.5 mm and 7.3 ± 1.6 mm, respectively 4. The investigators hypothesized that equivalence was of clinical significance if the difference in the initial cervical width was less than 1 mm among groups with the standard deviation of the initial cervical width of 1.6 mm. The estimated sample size was 47 patients in each group; this would be able to detect an equivalent effect in the groups with a power of 80% and a type 1 error (a) of 0.017. Data are expressed as the mean ± SD (standard deviation) or median with range or as the number (%) of cases.