CORTISOL, CORTISONE, AND 11-DEOXYCORTISOL LEVELS IN HUMAN UMBILICAL AND MATERNAL PLASMA IN RELATION TO THE ONSET OF LABOUR

Summary Levels of unconjugated cortisol, cortisone and 11-deoxycortisol were measured in umbilical arterial and venous plasma, and in maternal antecubital and uterine venous plasma by a method specific for each steroid, utilizing competitive proteinbinding radioassay following steroid fractionation by column chromatography. Samples were obtained (1) at elective Caesarean section, (2) at vaginal delivery or emergency Caesarean section after induced labour, and (3) at vaginal delivery or emergency Caesarean section after labour of spontaneous onset. In the umbilical circulation there was no significant arteriovenous difference for any of the steroids measured. There were significantly higher (p