Continuous infusion of 17-hydroxyprogesterone caproate into either the fetoplacental or intervillous circulation of a placental cotyledon attenuates vasoconstriction of the fetoplacental arteries by thromboxane mimetic U46619

Pretreatment of either the fetal or maternal circuits of the placenta with 17-P attenuates U46619-mediated fetoplacental vasoconstriction.