The abortifacient effect of synthetic androstane derivatives in the baboon.

Synthetic androstane derivatives have been tested for their ability to induce abortion during early pregnancy in primates. Two compounds were studied following intramuscular (IM) and oral treatment in fourteen baboons. A five-day treatment regimen was started at approximately day 20 of pregnancy in 12 baboons, with treatment delayed until after day 40 in two baboons. All seven baboons treated IM with either compound aborted following intramuscular treatment, although three required a second treatment series beginning on approximately day 40 of pregnancy. Two of five baboons treated orally aborted following the single treatment series initiated around day 20 of pregnancy. The two baboons treated only after day 40 continued to term and delivered healthy infants. These compounds are therefore effective at terminating pregnancy when given around the time of the missed menstrual period. Further studies are necessary to determine optimal dose and treatment schedule.