Maternal plasma and amniotic fluid prolactin levels in normal and hypertensive pregnancy.

Prolactin levels in the plasma and amniotic fluid of 121 normal pregnant women, 78 women with pre-eclampsia and 30 women with essential hypertension complicating pregnancy were determined by radioimmunoassay. Mean prolactin levels in plasma, but not in amniotic fluid, were significantly lower than controls in the group with pre-eclampsia (P less than 0.01) and in the group with essential hypertension (P less than 0.05). These findings suggest altered production and/or clearance of prolactin from the maternal compartment in these patients and may explain their increased response to pressor agents.