Abstract Background. Medical termination of pregnancy can be successfully performed with a combination of mifepristone (RU 486) and a prostaglandin analogue. We conducted a prospective, randomized trial to compare oral with vaginal administration of the prostaglandin E1 analogue misoprostol for first-trimester abortion in women treated initially with mifepristone. Methods. The study population consisted of 270 women seeking abortion within 63 days after the onset of amenorrhea. The dose of mifepristone was 600 mg, and the dose of misoprostol was 800 mg. The study had two primary end points: expulsion of the conceptus without the need for a surgical procedure, and abortion within four hours after the administration of misoprostol.
