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Intravenous infusion of prostaglandins (PG) for pregnancy termination has been associated with long duration of infusion and side effects (nausea, vomiting, diarrhea, and erythema at the site of injection). Some of these side effects have been eliminated through the use of intravaginal and intrauterine administration of PGs. The authors studied the effects of intraamniotic administration of PG on the 2nd trimester pregnant uterus based on the observations that PGE2 and F2alpha are found in samples of amniotic fluid obtained during spontaneous abortion. Single intraamniotic administration of 2.5-5.0 mg PGE2 or 25 mg PGF2alpha in 10 women 13-22 weeks pregnant stimulated uterine contraction and resulted in abortion in every case. 8 women had complete abortion and 2 necessitated manual removal of the placenta. Injection-abortion interval ranged from 4-1/2-18 hours, with a mean of 11.4 hours. 4 women experienced nausea and 3 had vomiting. There were no other side effects. This route of administration appears to produce a local action on the uterus, and the procedure does not require withdrawal of any amniotic fluid.

Induction of midtrimester abortion with a continuous intravenous infusion of prostaglandin (PG) was described by Karim and Filshie and Roth-Brandel et al. in 1970, but the effective dose of PGF2alpha was associated with side effects severely limiting clinical usefulness. Karim and Sharma induced abortion by intravaginal PG, but again this route also seemed complicated by severe side effects. Independent reports followed of successful induction of midtrimester abortion by intraamniotic PGF2alpha and PGE2 with few side effects. Although we also successfully induced abortion in 20 patients with a single intraamniotic instillation of 40 mg PGF2alpha, there is a potential hazard in this method; i.e., PG may leak from the amniotic cavity around the catheter and pass in large quantity into the systemic circulation, resulting in undesirable, severe side effects. A more reasonable and effective method would be to inject the PGF2alpha directly at the target organ, the myometrium, by extraovular administration. Side effects could thus be minimized and effective doses of PG reduced. Such intrauterine extraovular administration of PG has been reported. The incidence of side effects was greatly reduced, although the instillation of PG was required every 1-3 hours and there were some incomplete abortions. The investigation of extraovular PGF2alpha administration for induction of abortion in gestations between 12 and 16 weeks has been especially interesting. The procedure outlined by Wiqvist and Bygdeman and Embrey and Hillier was the 1 that the authors followed initially. 250 mcg PGF2alpha was instilled initially and was followed by 750 mcg in 5 minutes and 1 mg in 30 minutes. 1 mg was then instilled at 6 hour intervals. However, the failure rate with this dosage schedule was quite high. There was a good initial uterine response, but during the administrationsat 12, 18, and 24 hours, the response diminished considerably . The frequency of administration was then increased to every 2-3 hours and the amount instilled was increased to 2-3 mg. Although somewhat more successful than the original dose schedule, this method was also unsatisfactory. It appeared from our results that the closer the injections, the higher the success rate. Thus, a brief case report is presented using continuous extraovular administration of PGF2alpha with a Harvard pump, and the results indicate it is quite satisfactory. The patients complained of very little pain and side effects have been slight. The mean abortion time for 15 patients was 14 hours. The mean time for multiparas, 11.7 hours, was faster than the 15.8 hours for primiparas.

A particular concern of gynecologists is the increased incidence of spontaneous midtrimester abortion following vaginal termination, especially in primigravid women between 10-14 weeks gestation. Intraamniotic prostaglandins (PG) have been reported to be particularly effective, but abortion is not guaranteed to occur within 24 hours after a single injection and repetition of therapy or intravenous oxytocin may be required to complete the process. A new method, intraamniotic PGE2 (10 mg) combined with urea (80 g) has been tested in a small group (n=5) of primigravid women aged 17-22 and with gestational size of 17-20 weeks. PGE2 alone was administered in another group (n=5) with similar age, parity, and gestation. The combined regimen had a significantly shorter mean time to abortion (8 hours 2 minutes) compared to the PG alone therapy (22 hours, 14 minutes) (t=2.731, p0.05). Abortion was complete in the combined regimen but was incomplete in the PG alone regimen.