Fetal and maternal plasma cortisol levels during labour and after delivery in the human.

In a group of 15 cases the cortisol concentrations were determined in fetal and maternal plasma during labour and after delivery. In maternal plasma the levels were about twice as high as in fetal plasma and rose up to more than 1000 mug/l during labour (x = 639 +/- 222). After delivery the concentrations decreased. In fetal plasma, cortisol increased during labour from x = 173 +/- to x = 276 +/- 75 at the time of delivery and decreased to x = 106 +/- 36 within the first 23 hours. In a second group of 20 cases maternal and umbilical cord blood and blood of the newborn during the first 28 hours after delivery were analyzed. The values were in the same ranges as in the first group. Extremely high maternal levels were not correlated to higher fetal values. The cortisol levels of postmature children did not significantly differ from those of normal babies.