A medical method of early pregnancy termination using tamoxifen and misoprostol

A study was undertaken to determine whether ingestion of the selective estrogen receptor modulator tamoxifen followed by vaginal administration of the prostaglandin misoprostol would be an effective medical method of elective termination of early pregnancy. A clinical trial was conducted with a study group of 100 healthy women with pregnancies of 56 days gestational age or less who desired elective pregnancy termination. Each subject ingested 20 mg of tamoxifen once daily for 4 days followed 4 days later by intravaginal placement of four 200 micrograms tablets of misoprostol. If abortion did not occur within the next 24 h a second dose of 800 micrograms of misoprostol was given. The main outcome measures were incidence of complete abortion, hemoglobin levels, duration of vaginal bleeding, and incidence of side effects. Complete abortion occurred in 92 (92%, 95% CI 86.7, 97.3%) of 100 subjects. Of these 92 women, four aborted after ingesting tamoxifen without use of misoprostol, 84 within 24 h after receiving a single dose of misoprostol, one 21 days following a single dose of misoprostol, and three after a second dose of misoprostol was administered. There were six (6.0%) complete treatment failures and two (2%) incomplete abortions that required a dilatation and curettage. The mean duration of uterine bleeding was 8.1 days (range 1-34 days) and there was a median decrease in hemoglobin level of 0.50 g/dL (+2.2 to -4.7 g/dL). Vomiting occurred in 28% of subjects and diarrhea in 8%. These initial data suggest that ingestion of tamoxifen followed by intravaginal misoprostol may be an effective, easily administered, and inexpensive method to electively induce complete abortion in pregnancies of 56 days gestational age or less. Additional studies are necessary to determine whether the addition of tamoxifen increases the success rate compared with that obtained with the use of vaginally administered misoprostol by itself.