Neurodevelopment after moderate hyperbilirubinemia at term.

BACKGROUND: The aim of this work was to investigate in a prospective study whether moderate hyperbilirubinemia in healthy term neonates is associated with an increase of minor neurological dysfunction (MND) and behavioral problems up to 18 mo.

METHOD: We enrolled 43 healthy term infants with a bilirubin level ≥ 220 µmol/l (BILI group) at 72-96 h postnatally at the University Medical Center Groningen (UMCG), including eight referrals for hyperbilirubinemia. Seventy healthy term infants born at the UMCG with bilirubin level <220 µmol/l served as comparisons (COMP group). We evaluated the neurologic condition neonatally and at 3 and 18 mo; behavior was evaluated at birth and 18 mo.

RESULTS: Rates of MND in BILI and COMP groups were similar at all ages. However, bilirubin levels of ≥ 300 µmol/l (n = 10) were associated with an increased risk of complex MND (odds ratio: 4.21; 95% confidence interval: 1.02-17.37). Neonatally, BILI infants were more often lethargic than COMP infants (odds ratio: 3.54; 95% confidence interval: 1.32-9.51); at 18 mo, they had higher hyperactivity scores (effect: 0.32; 95% confidence interval: 0.08-0.56).

CONCLUSION: Occurrence of complex MND at 18 mo in infants with moderate hyperbilirubinemia was not different from that in comparison infants, but bilirubin level ≥ 300 was associated with an increased risk of complex MND. This study also suggests that minor behavioral effects of moderate hyperbilirubinemia cannot be excluded.