Exaggerated jaundice in Navajo neonates. The role of bilirubin production.

We have explored further the mechanism of exaggerated neonatal hyperbilirubinemia in the Navajo by determining bilirubin production rates with measurements of endogenous carbon monoxide excretion. Navajo newborns had elevated serum bilirubin concentrations and endogenous carbon monoxide excretion measurements at 2 days of age compared with a Caucasian control population. These findings could not be explained by differences in gestational age, postnatal age, or hemoglobin concentration. We conclude that accentuated bilirubinemia in Navajo neonates is partially due to increased bilirubin production.