Hormone production during pregnancy in the primigravid patient. I. Plasma levels of progesterone and 5α-pregnane-3,20-dione throughout pregnancy of normal women and women who developed pregnancy-induced hypertension

The plasma concentrations of progesterone and 5α-pregnane-3,20-dione (5α-dihydroprogesterone) were measured from as early as 12 weeks through 41 weeks of gestation in primigravid women. Two groups of primigravid women were assessed, those with uncomplicated pregnancies and those who developed pregnancy-induced hypertension. Plasma levels of progesterone and 5α-dihydroprogesterone rose progressively throughout gestation in both groups of women. The ratio of the level of progesterone to that of 5α-dihydroprogesterone in individual plasma samples of women with uncomplicated pregnancies was 7.0 from 12 to 15 weeks' gestation while at 35 to 41 weeks' gestation the ratio had declined to 4.6. Similar results were obtained in plasma samples of women who ultimately developed pregnancy-induced hypertension. Since no differences in plasma levels of progesterone or 5α-dihydroprogesterone were detected between primigravid women with uncomplicated pregnancies and those who developed pregnancy-induced hypertension, we conclude that neither progesterone nor 5α-dihydroprogesterone concentrations in plasma are of value in identifying women at risk of developing pregnancy-induced hypertension.