Intramuscular Administration of 15(S) 15 Methyl Prostagladin E2 Methyl Ester for Induction of Abortion: A Comparison of Two Dose Schedules

Abstract

Due to the need for an effective and safe parental administration technique, 2 intramuscular dose schedules of prostaglandin 15(S)ME2 were evaluated for practicability. 30 physically healthy women, ranging in age from 18-42 years, who were 8-22 menstrual weeks' gestation, had abortions at the Clinical Research Unit of the University of North Carolina Memorial Hospital. The women were treated according to 1 or 2 intramuscular prostaglandin (PG) 15(S)ME2 dose schdules. The 20 subjects in group 1 received 5 mc of PG 15(S)ME2 initially and at 4-hour intervals until abortion of the fetus or for a maximum of 48 hours. The 10 subjects in group 2 received 10 mc of PG 15(S)ME2 initially and at 8-hour intervals until abortion of the fetus or for a maximum of 48 hours. Subjects were monitored for signs of PG 15(S)ME2 toxicity and uterine contractions. 6 subjects from each group were continuously monitored in duplicate for intra-amniotic pressure by the open-end catheter technique. 4 criteria of abortifacient efficacy were used to compare the 2 dose schedules: the proportion of subjects aborting within the initial 24 hours, the proportion of subjects aborting within 48 hours, the mean abortion time of those subjects who aborted, and the cumulative abortion rate. Within 24 hours of the initial injection, 13 of the 20 group 1 subjects and only 2 of the 10 group 2 subjects aborted. Within 48 hours, 17 of the group 1 and 5 of the group 2 subjects aborted. The differences in the cumulative abortion rates between the 2 groups were significant at 24 and at 48 hours. Since constant monitoring of intrauterine pressure showed no significant differences in the mean frequency, intensity, tonus, or total uterine activity between the 2 groups or between subjects who aborted or failed to abort, it seems doubtful that constant intra-amniotic pressure monitoring will be useful in further defining the most practicable dose schedule.