Elevated venous concentrations of vasoactive intestinal polypeptide in cord blood of infants with fetal distress.

Concentrations of vasoactive intestinal polypeptide (VIP) in cord plasma were determined in 70 neonates (birth weight, mean +/- SD, 3,213.5 +/- 50.9 g, gestation 39.5 +/- 0.2 weeks), 22 of whom had fetal distress. Arterial VIP levels in cord blood were not significantly different between infants with and without fetal distress. The mean venous VIP in cord blood of distressed infants (28.1 +/- 8.4 pg/ml, mean +/- SE) was significantly (p < 0.05) higher than that of normal neonates (12.6 +/- 3.4 pg/ml). The mean placental content of VIP was 5.1 +/- 0.3 ng/g wet tissue, although a correlation with the venous concentration in the cord was not demonstrated. Venous VIP levels were elevated 24 h after birth (34.6 +/- 13.7 pg/ml) and decreased on the 5th day of life to 12.9 +/- 3.8 pg/ml, which was not significantly different from the mean VIP level in childhood (14.7 +/- 3.1 pg/ml). These results demonstrate that, in the perinatal period, plasma VIP levels are elevated on two occasions: at delivery associated with fetal distress (cord vein), and at 24 h of age. VIP in the former seems to be of placental and/or maternal origin.