Objective: To compare the impact of 200 and 400 microg oral misoprostol on pre-operative cervical priming in both primi- and multigravidae prior to first trimester termination of pregnancy. Pre-operative cervical dilatation and bleeding were assessed.
Design: Randomised controlled trial.
Setting: Norwegian university teaching hospital.
Sample: Five hundred and fifty-one women undergoing surgical termination of pregnancy between 7 and 12 weeks of gestation.
Methods: Patients were randomised to either 200 or 400 microg of oral misoprostol 10-16 hours before vacuum aspiration. The degree of cervical dilatation prior to abortion by vacuum aspiration was measured. Pre-operative bleeding and pain were recorded and vaginal bleeding was measured.
Main outcome measures: Degree of pre-operative cervical dilatation and pre-operative bleeding.
Results: The mean cervical dilatation was 5.8 mm (SD 1.7) for the women who received 400 microg misoprostol and 5.4 mm (SD 1.4) for those who received 200 microg (P= 0.004). The pre-operative dilatation was larger in multigravidae than in primigravidae in both dosage groups. The odds ratio (OR) of pre-operative bleeding was 3.3 (95% confidence interval [CI] 2.1-5.0) in the 400 microg dosage group, as compared with the group receiving 200 microg misoprostol. The occurrence of bleeding was dose-dependent. Frequency of bleeding was similar in multigravidae compared with primigravidae in the 400 microg dosage group, whereas the occurrence of bleeding was less in primigravidae than multigravidae in the 200 microg dosage group. Only 89 out of 551 patients bled one or more grams. The volumes measured were not statistically significantly different. Complications were minor, and were distributed equally between the two dosage groups.
Conclusions: The 200 microg oral misoprostol compared with the 400 microg oral misoprostol given 10-16 hours before first trimester surgical abortions results in less pre-operative vaginal bleeding and in a statistically, although not clinically significant reduction in cervical dilatation.