Increased bilirubin production, ceruloplasmin concentrations and hyperbilirubinaemia in full-term newborn infants.

Ceruloplasmin possesses antioxidant activity in vitro, but such a property has not been substantiated in vivo so far. However, it has been suggested that the lack of factors protective against oxidative haemolysis might have a role in neonatal hyperbilirubinaemia. Ceruloplasmin and alphafetoprotein concentrations were measured in cord blood in 78 unselected full-term singleton newborn infants without G6PD deficiency and haemolytic disease of the newborn; in the same infants, the carboxyhaemoglobin level was assessed on the fourth day of life and taken as an index of bilirubin production. The relationship between these variables and maximum bilirubin level in the first 4 days was studied by multiple regression analysis. High carboxyhaemoglobin levels and low ceruloplasmin concentrations, but not alphafetoprotein resulted, associated with hyperbilirubinaemia (P < 0.001). No relationship was found between carboxyhaemoglobin and ceruloplasmin levels. These results exclude an important role for ceruloplasmin in protecting against possible oxidative haemolysis in full-term newborn infants. Ceruloplasmin levels in cord blood are most probably related to hepatic metabolism and are better predictors of hyperbilirubinaemia than alphafetoprotein concentrations.