Mifepristone and misoprostol compared with misoprostol alone for second-trimester abortion: a randomized controlled trial.

OBJECTIVE: To estimate the clinical benefit of pretreatment with mifepristone followed by misoprostol compared with misoprostol alone for second-trimester abortion.

METHODS: Two hundred sixty women with live fetuses of gestational ages 14-21 weeks were enrolled in a randomized, placebo-controlled, double-blind trial in Vietnam. Eligible consenting women received either mifepristone or placebo to take on their own at home and were scheduled to return to the hospital the next day. At the hospital, women were given 400 micrograms buccal misoprostol every 3 hours, up to five doses, until both the fetus and placenta were expelled. Efficacy was evaluated 15 hours after misoprostol dosing began and the procedure was considered complete if uterine evacuation was achieved without recourse to surgical evacuation.

RESULTS: Pretreatment with mifepristone resulted in more than twice the chance of complete uterine evacuation in 15 hours (79.8% compared with 36.9%, relative risk 2.16, 95% confidence interval 1.70-2.75). The mean induction-to-abortion interval for complete uterine evacuations was statistically significantly shorter among participants pretreated with mifepristone compared with those given misoprostol alone (8.1, standard deviation 2.8, range 2.5-14.8; and 10.6, standard deviation 2.5, range 6.5-15.5 hours, respectively; P<.001). The side-effect profiles for the two regimens did not differ significantly and acceptability of the treatments was high.

CONCLUSION: Mifepristone-misoprostol is more efficacious and faster than misoprostol alone. Services offering home administration of mifepristone as pretreatment could optimize efficacy and acceptability of medical abortions for women with gestations 14-21 weeks since the last menstrual period.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00784186.

LEVEL OF EVIDENCE: I.