Methotrexate and misoprostol for early abortion.

Methotrexate is cytotoxic to trophoblast and, in low doses, has minimal side effects. It is used to treat both gestational trophoblastic neoplasia and ectopic pregnancy. The cytotoxic effects of methotrexate on intrauterine trophoblast should be equivalent. To test this hypothesis, ten pregnant women, < 8 weeks' gestation were treated with methotrexate 50 mg/m2 intramuscularly followed 3 days later by misoprostol, a prostaglandin E1 analogue. The first 4 patients received misoprostol 600 micrograms orally; none aborted soon after the misoprostol. Two patients aborted 25 and 26 days after the methotrexate injection and two elected a suction abortion after 14 days (one by choice and one because the pregnancy was still viable). The last 6 patients received misoprostol 800 micrograms vaginally and aborted within 3-8 hours. One patient had an incomplete abortion requiring a suction curettage 34 days after the misoprostol. Vaginal bleeding for these 6 patients lasted an average of 29 +/- 11 days (range, 12-42 days). No methotrexate side effects were observed. Vaginal misoprostol (800 micrograms) was significantly more effective (p = 0.005) than oral misoprostol (600 micrograms) in effecting abortion after intramuscular methotrexate.