Concentrations of human atrial natriuretic peptide in the cord blood and the plasma of the newborn.

Concentrations of human atrial natriuretic peptide (hANP) in the cord blood and the plasma were measured in 25 newborns. The level of hANP in 0 to 1 post-natal days (212.8 +/- 118.1 pg/ml; mean +/- SD) was significantly higher than that in cord blood (69.7 +/- 53.2 pg/ml) (p less than 0.005). There were no significant differences in the levels of hANP at the ages of 0 to 1, 4 and 6 post-natal days. The level of hANP did not show any significant correlation with urinary excretion of Na, urinary Na/Cr or Na/K ratios. Further evaluations should be made in order to clarify the role of hANP during the early post-natal period.