One- and two-day mifepristone–misoprostol intervals for second trimester termination of pregnancy between 13 and 16 weeks of gestation

ObjectiveTo compare the efficacy of 1-day and 2-day mifepristone and misoprostol intervals for second trimester termination of pregnancy between 13 and 16 weeks.MethodsA prospective randomized cohort study of 100 women who underwent voluntary termination between 13 and 16 weeks of gestation. Patients were randomly assigned to receive 200 mg of oral mifepristone, followed 1 day (group 1) or 2 days (group 2) later by 600 μg of vaginal misoprostol. All patients received 400 μg of oral misoprostol every 6 hours for a maximum of 2 doses. Main outcome measure was successful abortion rate at 24 hours after the start of misoprostol treatment. Secondary outcome measures were induction-to-abortion interval and frequency of adverse events.ResultsThe 24-hour successful abortion rate was similar between groups 1 and 2 (47 [94%] vs 50 [100%]; P = 0.241). The mean misoprostol-to-abortion interval was also similar (7.0 ± 3.0 vs 6.8 ± 4.3 hours; P = 0.744). Among the 86 patients for whom histological examination of the products of conception was performed, retained chorionic villi rates were higher in the 1-day regimen group compared with the 2-day regimen group (46.2% [18/39] vs 29.8% [14/47]; P < 0.001).ConclusionA 2-day mifepristone–misoprostol interval resulted in fewer incomplete abortions than a 1-day interval for second trimester termination of pregnancy between 13 and 16 weeks.