WHO multinational study of three misoprostol regimens after mifepristone for early medical abortion. I: Efficacy

Abstract

To compare the efficacy of oral and vaginal administration of misoprostol after a single oral dose of 200 mg of mifepristone and to investigate whether the efficacy can be improved and the duration of bleeding shortened by continuing oral misoprostol for one week. Double blind, randomised controlled trial. Fifteen gynaecological clinics in 11 countries. A total of 2219 healthy pregnant women requesting medical abortion with < or =63 days of amenorrhoea. Mifepristone 200 mg administered orally on day one, followed by 0.8 mg misoprostol either orally or vaginally on day three. The oral group and one of the vaginal groups continued with 0.4 mg of oral misoprostol twice daily for seven days. Complete abortion was the main outcome. Secondary outcomes were side effects, timing of expulsion and duration of bleeding. The crude complete abortion rate was 92.3% in the oral plus continued oral misoprostol group, in the vaginal-only group it was 93.5%, and it was 94.7% in the vaginal group that continued with oral misoprostol, when considering undetermined cases as failures. Among women with amenorrhoea length > or =57 days, the risk of failure of complete abortion was almost three times higher in the oral plus continued oral misoprostol group (RR = 2.8, 95% CI 1.3 to 5.8), and over two times higher in the vaginal-only group (RR = 2.2, 95% CI 1.0 to 4.7), when compared with the vaginal plus continued oral misoprostol group. Among women with amenorrhoea length < 57 days, the differences were not significant. Timing of expulsions and duration of bleeding were similar in the three groups. For amenorrhoea length > or =57 days, vaginal misoprostol is more effective than oral when continued with 0.4 mg oral misoprostol twice daily for seven days. Misoprostol continuation improved the efficacy in this amenorrhoea group compared with a single dose of vaginal misoprostol on day three, but it did not shorten the duration of bleeding. No differences in efficacy were observed when amenorrhoea length was < 57 days.