Prostaglandins and abortion. III. Comparison of single intra-amniotic injections of 15-methyl prostaglandin F2alpha and prostaglandin F2alpha for termination of second-trimester pregnancy: an international multicenter study. World Health Organization Tast Force on the Use of Prostaglandins forthe Regulation of Fertility.

A multicenter, multinational study involving 1,521 patients has compared prostaglandin F2alpha (PGF2alpha) (40 or 50 mg.) and 15-methyl PGF2alpha (2.5 mg.) given intra-amniotically for induction of second-trimester abortion. The highest success rates for PGF2alpha at 24 and 48 hours were 67.8 and 86.6 per cent, respectively. The percentages for 15-methyl PGF2alpha for the equivalent times were 74.1 and 95.6 per cent, respectively. There were 75 cases classified as failures in 602 patients treated with PGF2alpha and only 34 cases were classified as failures among 919 patients treated with 15-methyl PGF2alpha. A further 35 patients required additional treatment to complete the abortion. The over-all incidence of diarrhea and vomiting was low, less than 3.4 episodes per patient. There were 20 cases of cervical laceration (2.9 per cent); only one extended into the lower segment of the uterus. It is concluded that intra-amniotic administration of either 50 mg. of PGF2alpha or 2.5 mg. 15-methyl PGF2alpha provides an effective and safe method for termination of second-trimester pregnancies.