Moderate hyperbilirubinemia induces a transient alteration of neonatal behavior

To investigate the behavioral changes induced by moderate hyperbilirubinemia in the otherwise healthy, untreated newborn infant.

Fifty term neonates (23 boys) with untreated moderate hyperbilirubinemia (median: 14.3 mg/dL; range: 13.2-20 mg/dL) and 50 matched control subjects with lower bilirubin concentrations (median: 9.1 mg/dL; range: 5.3-12 mg/dL) were administered the Brazelton Neonatal Behavioral Scale at 87 hours of life (range: 72-110 hours). A subgroup analysis was also performed at 104 hours of life (range: 96-134 hours) and at 3 weeks of age.

At the first examination, all behavioral clusters were significantly altered in the group with moderate hyperbilirubinemia. The visual and auditory capabilities of the hyperbilirubinemic infant were especially compromised. Although social-interactive cluster scores significantly correlated both with serum bilirubinemia and birth weight, the former accounted for 8.7% of the variance and the latter accounted for only 4.7%. The moderate hyperbilirubinemia neonates' scores also showed a negative correlation with the autonomic system and more frequent presence of tremors. After 24 hours, a decrease in serum bilirubin within the moderate hyperbilirubinemic group was associated with improved scores. At 3 weeks of age, the behavioral assessment of the 2 groups did not show significant differences.

Untreated moderate hyperbilirubinemia is associated with a transient and apparently reversible alteration of neonatal behavior, particularly in the social-interactive area.