BIOCHEMICAL-CHANGES IN THE MOTHER AND THE FETUS DURING LABOR AND ITS SIGNIFICANCE FOR THE MANAGEMENT OF THE 2ND STAGE

In 69 patients with uneventful pregnancies, term labor was studied prospectively with respect to length of second stage, number of bearing down efforts, maternal and fetal levels of lactate, epinephrine and norepinephrine. Maternal venous blood concentrations were measured in early labor and at the time of delivery while samples from umbilical artery and vein provided fetal blood. There was a significant rise of lactate and catecholamines in maternal blood during labor and at delivery fetal lactate concentration was lower than the maternal level while for epinephrine and norepinephrine fetal levels were higher. For all three compounds umbilical artery concentrations were higher than umbilical venous levels. While there was no correlation between the biochemical parameters in maternal blood and length of second stage maternal lactate and norepinephrine concentration at the time of delivery significantly correlated with the number of bearing down efforts. Umbilical artery lactate correlated with both, length of second stage and number of bearing down efforts. © 1990.