Abstract
Urinary estradiol 17-sulfate (ES) concentration during a pregnancy was measured by radioimmunoassay using a highly specific antiserum to ES. The ES levels rose gradually from the 6th gestational month, and such levels in late pregnancy became over four-times higher than those in non-pregnant women. The ES concentration at the 7, 8, 9 and 10th gestational months were 15.0±2.3, 17.0±2.2, 23.5±2.4, and 41.1±4.7ng/ml (mean±SE), respectively. After delivery, the urinary ES rapidly decreased; the values at 8 and 24 hours after delivery were 7.0±0.9 and 5.8±0.6ng/ml, respectively, or almost at the same levels in non-pregnant women. The physiological role of the ES production during a period of pregnancy is described herein.
