INDUCTION OF ABORTION WITH MIFEPRISTONE (RU-486) AND ORAL OR VAGINAL MISOPROSTOL

Background. Medical termination of pregnancy can be successfully perfo rmed with a combination of mifepristone (RU 486) and a prostaglandin a nalogue. We conducted a prospective, randomized trial to compare oral with vaginal administration of the prostaglandin E(1), analogue misopr ostol for first-trimester abortion in women treated initially with mif epristone. Methods. The study population consisted of 270 women seekin g abortion within 63 days after the onset of amenorrhea. The dose of m ifepristone was 600 mg, and the dose of misoprostol was 800 mu g. The study had two primary end points: expulsion of the conceptus without t he need for a surgical procedure, and abortion within four hours after the administration of misoprostol. Results. Expulsion of the conceptu s without the need for a surgical procedure occurred in 95 percent of the women who received misoprostol vaginally and in 87 percent of thos e who received it orally (P=0.03). The rate of continued pregnancy was 7 percent with the oral regimen and 1 percent with the vaginal regime n (P=0.01). Ninety-three percent of the women receiving misoprostol va ginally had abortions within four hours, as compared with only 78 perc ent of the women receiving the drug orally (P<0.001). Vomiting and dia rrhea were reported more frequently by the women who received oral mis oprostol than by those who received vaginal misoprostol (P=0.04 and P= 0.002, respectively). Conclusions. After the administration of mifepri stone, vaginal administration of misoprostol is more effective and bet ter tolerated than oral administration for the induction of first-trim ester abortion.