Developmental follow-up of breastfed term and near-term infants with marked hyperbilirubinemia.

OBJECTIVE: In recent years, the increased prevalence of breastfeeding in conjunction with early discharge practices has increased the risk for marked hyperbilirubinemia in neonates. This has resulted in the potential for bilirubin brain injury in affected infants. The purpose of this study was to identify all infants >/=36 weeks' gestational age with bilirubin levels >25 mg/dL and evaluate them for early and late evidence of bilirubin brain injury.

METHODS: We reviewed the charts of all infants (from 1993-1996) >/=36 weeks' gestational age who were readmitted to the hospital during the first week of life with bilirubin levels >25 mg/dL. Readmission records were reviewed for early signs of bilirubin encephalopathy. Magnetic resonance imaging (MRIs) and Brainstem auditory-evoked responses (BAERs) were reviewed for evidence of bilirubin toxicity. At follow-up, study infants had a complete neurodevelopmental examination, repeat MRIs, and behavioral hearing evaluations.

RESULTS: From 1993 to 1996, we identified 6 term and near-term infants readmitted to the hospital within the first week of life with peak bilirubin values ranging from 26.4 mg/dL (451 micromol/L) to 36.9 mg/dL (631 micromol/L). Five of 6 infants had bilirubin values >30 mg/dL (513 micromol/L). All were exclusively breastfed or fed a combination of breast and bottle feedings. Five of 6 infants presented with abnormal neurologic signs. Four infants had initial MRIs, 3 of whom had increased signal intensity in the basal ganglia consistent with kernicterus. Two infants had abnormal BAERs; both also had abnormal MRIs. Five of 6 infants received exchange transfusions and all were treated with phototherapy and intravenous fluids. Follow-up examinations between 3 months and 2 years showed resolution of clinical signs in all but 1 infant. Four infants had a subsequent normal MRI and 1 had residual hearing impairment. One infant demonstrated severely abnormal developmental evaluations, as well as both an abnormal initial MRI and BAERs. Follow-up MRI showed evidence of encephalomalacia with changes not characteristic of kernicterus.

CONCLUSIONS: We observed transient neurologic abnormalities in 5 of 6 infants readmitted to the hospital during the first week of life with marked hyperbilirubinemia. The abnormalities resolved following aggressive management using hydration, phototherapy, and exchange transfusion and may not correlate with long-term prognosis. Less aggressive therapy may be associated with residual neurologic abnormalities. We speculate that inadequate establishment of breastfeeding coupled with early discharge practices may play a role in the development of marked hyperbilirubinemia in these infants.