MATERNAL AND UMBILICAL CORD PLASMA NORADRENALINE CONCENTRATIONS DURING LABOUR WITH AND WITHOUT SEGMENTAL EXTRADURAL ANALGESIA, AND DURING CAESAREAN SECTION

Serial measurements of maternal and umbilical cord plasma noradernalineconcentrations were obtained in 10 patients undergoing normalvaginal delivery with segmental extradural analgesia, in 10patients undergoing normal vaginal delivery without extraduralanalgesia, and in 12 patients undergoing elective Caesareansection under general anaesthesia. Maternal noradrenaline concentrationsincreased significantly during delivery in all three groups,the peak concentrations occurring at delivery. However, theincrease in the maternal noradrenaline concentration duringdelivery in the extradural group was lower than in the non-extraduralgroup (P<0.05). Umbilical venous and arterial concentrationsof noradernaline were lower after Caesarean section than aftervaginal delivery. However, extradural analgesia did not affectthe fetal noradrenalinc concentrations. Since noradrenalineis probably required for the adaptation of the newborn to extrauterinelife, the unaltered fetal response may be beneficial.