Cortisol, cortisone, and 11-deoxycortisol levels in human umbilical and maternal plasma in relation to the onset of labour.

Abstract

SummaryLevels 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<0.001) umbilical cord cortisol levels at vaginal delivery after labour of spontaneous onset (149±13ng./ml.; mean ±S.E.M.) than after induction of labour (65 ± 9 ng./ml.) and in both these groups, the concentration of cortisol in the umbilical cord was higher than at elective Caesarean section (26 ± 4 ng./ml.) If Caesarean section was performed during labour, cord cortisol levels were again higher (p<0 05) after labour of spontaneous onset (93 ± 9 ng./ml.) than after induced labour (67 ± 8 ng./ml.). Umbilical cord cortisone and maternal cortisol levels were more related to the process of labour itself rather than to its initiation since levels in induced labour or labour of spontaneous onset were equally high. Cortisol was quantitatively the most important 17‐hydroxycorticosteroid in the maternal circulation, whereas cortisone was quantitatively at least as important as cortisol in umbilical cord plasma.