Prostacyclin formation by the pregnant human myometrium.

Human myometrium taken between 15 and 42 weeks of pregnancy released a material in vitro which possessed anti-aggregatory activity. This material parallelled authentic prostacyclin in this action; it possessed a similar stability at alkaline pH and generation of activity was inhibited by indomethacin. Production of the prostacyclin-like material by the myometrium was similar at weeks 15 and 38 of pregnancy but a 4-fold increase in synthesis had occurred by 40 weeks. It is suggested this increase may be important for parturition.