The effect of a 10 cm2, 0.5% 15-ME-PGF2alpha methyl ester intravaginal silastic device on abortion and plasma prostaglandin concentration.

Intravaginal insertion of a 10 cm2 silastic device with an 0.5% concentration of 15(S)-15-methyl-prostaglandin F2alpha methyl ester alone successfully induced abortion in 27 of 48 patients in the midtrimester and in an additional 11 patients with a concomitant infusion of oxytocin. The mean abortion time for the 38 successful induction was 15.35 hours. In 8 of the 10 patients who failed to abort even with concomitant oxytocin therapy, abortion was induced by serial intramuscular injections of 15-ME-PCF2alpha; the remaining 2 failures underwent surgical evacuation. The plasma levels of 15-ME-PGF2alpha methyl ester in the 11 patients studied varied widely over the first 2 hours after insertion of the device. The maximum mean level was achieved at 2 hours, maintained at 4 hours and then dropped sharply at 8 hours and declined over the abortion period in undelivered patients. Vomiting and diarrhea were the most common side effects and in general well tolerated by the patients. However, there was an adverse reaction in a single patient who experienced almost constant nausea, vomiting and diarrhea. The device was removed 1 hour 50 minutes after insertion and the patient aborted spontaneously 7 hours later. Intravaginal insertion of a silastic device is an effective means of prostaglandin abortion, but further investigation is required to determine the most effective device which would provide a slow, continuous release of the prostaglandin.