OBJECTIVE: To compare the efficacy of the vaginal and sublingual administration of the synthetic prostaglandin misoprostol with the currently used oral administration route in second-trimester medical abortion.
METHODS: This was a prospective randomized trial of medical abortion with misoprostol after mifepristone priming at 14–24 weeks of gestation. From 2009 to 2013, recruited women received 200 mg mifepristone orally followed 24–48 hours later by an 800-microgram vaginal loading dose of misoprostol. Women were then randomized to receive additional 400-microgram misoprostol doses orally every 3 hours, vaginally every 4 hours, or sublingually every 3 hours. The main outcome was the duration of abortion with emphasis on the proportion of women undelivered 12 hours after the misoprostol loading dose in the three groups.
RESULTS: A total of 302 women were randomized: 100 to oral, 100 to vaginal, and 102 to sublingual misoprostol. The median gestation at recruitment was oral 19.1 weeks (interquartile range 17.2–20.8), vaginal 19.4 weeks (interquartile range 17.3–20.4), and sublingual 19.7 weeks (interquartile range 17.6–21.0). The overall abortion duration was longer in women receiving oral misoprostol: oral 9.5 hours (95% confidence interval [CI] 8.5–11.4), vaginal 7.4 hours (95% CI 6.5–8.2), and sublingual 7.8 hours (95% CI 7.0–9.2). Overall, 84 of 302 (27.8%) women were undelivered at 12 hours, comprising 37.0% (95% CI 28.7–47.8) oral, 20.5% (95% CI 14.0–30.1) vaginal, and 21.0% (95% CI 14.3–30.7) sublingual groups.
CONCLUSION: Vaginal or sublingual misoprostol administered after a vaginal loading dose in second-trimester medical abortion with mifepristone priming is associated with a shorter time to pregnancy termination compared with an oral regimen.
CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00864799.
LEVEL OF EVIDENCE: I