Maternal and fetal plasma renin and dopamine-beta-hydroxylase activities in toxemic pregnancy.

Toxemic and normotensive pregnant women were compared for plasma renin activity (PRA), aldosterone (PA), and dopamine-beta-hydroxylase (DBH). At term, hypertensive patients exhibited higher levels of PRA and PA, but similar levels of DBH, progesterone, and estradiol. Their elevated blood pressure was significantly correlated to their levels of PRA. During the delivery levels of PRA increased significantly in toxemic patients in spontaneous labor. Venous and arterial cord PRA levels were higher in babies born to hypertensive mothers than in babies born to normotensive mothers. Three days postpartum, maternal PRA level was lower than at term. Seven days postpartum, PRA levels remained higher in toxemic than in normal women. Maternal DBH levels did not change during and after delivery. Levels of DBH were undetectable in cord blood. We conclude that the renin-angiotensin system is involved in the pathogenesis of toxemia.