Reassessment of systemic administration of prostaglandins for induction of midtrimester abortion

Abstract

The present investigation was undertaken to evaluate the abortifacient efficacy of vaginal and intramuscular administration of different dose schedules of the 15-methyl analogues of prostaglandin F 2α. 1. Vaginal administration . Both 15-methyl-PGF 2α and 15-methyl-PGF 2α methyl ester can be absorbed from the vagina in sufficient amounts to induce abortion. The potency of the methyl ester was approximately twice that of the free acid. The most successful treatment schedule consisted of an initial dose of 0.5 mg of the methyl ester followed by 1.0 or 2.0 mg every third hour. On this treatment all patients aborted within 24 hours. 2. Intramuscular administration . Initially 200 μg of 15-methyl-PGF 2α was given. The dose was increased to 400 μg or occasionally to 500 μg depending on the effect and tolerance of the patient and repeated every third hour. The treatment schedule resulted in a 100 per cent abortion rate and the mean induction-abortion interval was 16.1 hours. Both routes were associated with a higher frequency of side effects than that reported for intra-amniotic administration of 15-methyl-PGF 2α. It seems justified to conclude that the intra-amniotic route is preferable after the 14th week when the uterine cavity is easy to puncture but that vaginal or intramuscular injections of the compounds could be an alternative in late first trimester and early second trimester cases.