THE STEROID HORMONAL MILIEU OF THE HUMAN FETUS AND MOTHER AT 16-20 WEEKS OF GESTATION

Abstract

The inter-relations of steroid hormone levels in plasma from mothers and their undisturbed fetuses during the second trimester of human pregnancy have not been defined previously. Maternal vein (MV), fetal artery (FA), fetal vein (FV) and amniotic fluid (AF) levels of progesterone (P), 17-OHP, 11 deoxycortisol (S), DOC, cortisone (E), cortiaol (F), corticosterone (B) and aldosterone (Aldo) were measured in microassays in 12 conscious but sedated mothers and their fetuses undergoing therapeutic termination of pregnancy at 16-20 weeks gestation. The study received the approval of the Hospital Ethical Committee and maternal consent for the studies was obtained in each case. FA and FV samples were obtained by direct vessel puncture through a fetoscope without fetal disturbance. FA levels of F and B were significantly higher (p<0.01) than in FV; FV levels of P and E were higher (p<0.01) than FA values. No significant differences between FV or FA were found for levels of DOC, 17-OHP or S. MV levels of Aldo, F and B were significantly higher, with values of P, 17-OHP, DOC and S significantly lower than those in either fetal vessel. AF values of F, B, S, Aldo and DOC tended to be lower than those reported previously from mothers undergoing routine amniocentesis. We conclude: there is evidence that the fetal adrenal cortex is functioning independently of the mother in mid-gestation; maternal premedicatlon may lower fetal stress hormone secretion.