Plasma cortisol and cortisone in pregnancies with normal and anencephalic fetuses.

Plasma cortisol (F), cortisone (E), and progesterone (P), were measured in the umbilical vein (UV), umiblical artery (UA), and maternal peripheral vein (MPV) of 17 normal patients, and of 8 patients carying anencephalic fetuses. The plasma F in MPV of patients undergoing vaginal delivery after labor of spontaneous onset was significantly higher than that of patients delivered by elective cesarean section, whereas the plasma F concentrations in the UA or UV of the 2 groups were not statistically different from each other. The anencephalic fetuses had UA plasma F and E concentrations which were significantly lower than those of normal fetuses, suggesting that a main portion of UA cortisol and cortisone originates in the fetal adrenal. The UV and MPV plasma F and E concentrations of patients carrying anencephalic fetuses did not differ, however, from those of normal patients, suggesting that these UV corticoids are derived mainly from maternal sources. The amniotic fluid cortisol levels of the patients carying anencephalic fetuses were lower than those observed in the normal pregnancies, suggesting that amniotic fluid cortisol is derived mainly from fetal sources.