Catecholamines in fetal blood during birth in man.

Catecholamines and pH were determined simultaneously in human fetal scalp blood during parturition and in umbilical artery blood at birth. During the course of six normal vaginal deliveries with relatively small changes in blood pH about a ten-fold increase in catecholamine concentration was found. During six deliveries complicated by falls in blood pH to < 7.25 much higher values were often encountered.