Corticotrophin-releasing hormone and ACTH levels in maternal and fetal blood during spontaneous and oxytocin-induced labour

The changes in corticotrophin-releasing hormone (CRH), ACTH and dehydroepia ndrosterone (DHEA) in maternal and fetal plasma were estimated in women und ergoing spontaneous and oxytocin-induced labour to correlate hormone change s with the mode of parturition. Blood was sampled from a maternal periphera l vein 2 days before labour, during the second stage of labour and on the s econd postnatal day. and also from umbilical vessels just after delivery. H ormone concentrations were measured by RIA and ELSA methods. The maternal p lasma CRH concentration before labour was significantly higher in the group of women delivered spontaneously and declined during the labour through to the second postnatal day. Measured in umbilical vessels, CRH as well as AC TH concentrations were higher in the umbilical vein than artery. The mean m aternal plasma ACTH was similar in both groups before delivery, then increa sed significantly in both groups during the labour, decreasing on the secon d day after delivery There were no changes in DHEA concentrations among the groups and at all time points of collection. No correlations between CRH a nd ACTH or DHEA were observed. Our results suggest that the maternal pituit ary can respond to stress factors during delivery but peripheral CRH, proba bly mainly of placental origin. is not a major modulator of pituitary actio n.