Midtrimester abortion induced by serial intravaginal administration of prostaglandin E2 suppositories in conjunction with a contraceptive diaphragm

Midtrimester abortion was successfully induced in a series of 20 patient by intra-amniotic instillation of 15(S)-15-methyl-prostaglandin F_2α with a mean abortion time of 17.78 hours. The patients in this study were divided into two groups, Groups I received on initial dose of 2.5 mg 15-ME-PGF_2α and aborted in a mean time of 16.26 hours. The patients in Group II received 3.0 mg 15-ME-PGF_2α and aborted in a mean time of 18.94 hours. There was no significant difference in the abortion time, occurrence of side effects or the initiation of uterine activity between Group I and Group II. Parous patients aborted somewhat faster than nulliparous patients but this difference was not significant. In this study 80% of the patients aborted in 24 hours or less, and the intra-amniotic instillation of 15-ME-PGF_2α was an effective abortifacient technique from the 15th to the 23rd week of gestation. The uterine response to intra-amniotic instillation of 15-ME-PGF_2α was characterized by the gradual appearance of low amplitude, high frequency contractions accompanied by a rise in baseline intrauterine tonus. Uterine activity developed gradually and peaked at 1:50 hours after intra-amniotic instillation of 15-ME-PGF_2α. In this small series 15-ME-PGF_2α administered via intra-amniotic instillation did not appear to have a distinct advantage over the naturally occurring PGF_2α administered by the same method for the induction of midtrimester abortion; a larger series is indicated to define the advantages of either technique.