Twenty-four-hour pattern of cortisol in the human fetus at term.

Objectives: Indirect evidence suggests that adrenal steroid production in the human fetus may have a circadian rhythm. To assess whether there is a 24-hour rhythm of fetal cortisol in the human fetus, we investigated the relationship between fetal and maternal cortisol and cortisone concentrations in maternal, umbilical arterial, and umbilical venous blood samples over a 24-hour period.

Study Design: Elective cesarean sections were scheduled every 2 hours around the clock in 57 term (38-41 weeks' gestation) nonlaboring pregnant women.

[The simultaneous measurement of cortisol and cortisone in the plasma and tissues by high-resolution liquid chromatography].

Measurement of cortisol (F) and cortisone (E) are important to study cortisol metabolism during gestation or in hypertensive patients. We developed a method for simultaneous measurement of F and E based on plasma extraction by dichloromethane, separation by high resolution chromatography and detection at 254 nm. Good correlation between this method and RIA was obtained in measurements of maternal plasma cortisol (r = 0.