Umbilical vein cortisol after spontaneous and induced labour and at elective Caesarean section.

Umbilical vein (UV) plasma cortisol levels were assayed at delivery after spontaneous labour, oxytocin-induced labour, prostaglandin E2-induced labour and after delivery by elective Caesarean section. Higher mean UV cortisol levels were observed after vaginal delivery than after delivery by elective Caesarean section. The highest mean UV cortisol level was observed in the PGE2 group which accords with the known ability of prostaglandins to increase steroid production. The significance of these findings is discussed.