Fetoplacental steroid metabolism in prolonged pregnancies

The response to an intravenous load of 50 mg of dehydroepiandrosterone sulfate given to women with a pregnancy prolonged to more than 42 weeks was compared to the response in control pregnant women at 40 weeks. The half-life of dehydroepiandrosterone sulfate was longer in the prolonged pregnancy group than in the control group (mean +/- SEM, 3.64 +/- 0.24 hour versus 2.78 +/- 1.08 hour, p less than 0.05), and the rises of serum free estrone and free estradiol 4 hours after infusion were less in the prolonged pregnancy group than in the control group. Maternal venous and umbilical venous estrone, estradiol, free estriol, and dehydroepiandrosterone sulfate levels were compared in samples from control, postmature, and postterm groups. Umbilical estriol concentrations were significantly less in the postmature group (67.8 +/- 9.5 ng/ml, mean +/- SEM) than in the control group (136 +/- 22.8 ng/ml, mean +/- SEM, p less than 0.01), but there were no significant differences between dehydroepiandrosterone sulfate, estrone, and estradiol levels. Maternal venous estriol levels were lower in the postmature group (13.3 +/- 2.1, p less than 0.05) than in the control group (25.0 +/- 4.9). A reduction in overall placental estrogen production was indicated by the results of the dehydroepiandrosterone sulfate loads in the patients with prolonged pregnancy, yet the normal umbilical venous estrone and estradiol levels do not fit this conclusion. There is no explanation for the discrepancy at this time.