Outcomes of Extremely Premature Infants Related to Their Peak Serum Bilirubin Concentrations and Exposure to Phototherapy

Objectives. To analyze, in extremely low birth weight infants, associations between peak bilirubin concentration and evidence of brain damage, and between peak bilirubin concentration and blindness attributable to retinopathy of prematurity.

Methods. Retrospective study of 128 infants of ≤800 g birth weight and ≤27 weeks gestation born between 1980 and 1989 and discharged from a tertiary neonatal intensive care unit. After screening analyses, multivariable analyses were conducted to identify associations between blindness and peak bilirubin concentration (dichotomized at different levels to create 3 binary variables), and between severe adverse neurodevelopmental outcome at 18 months postterm age and peak bilirubin levels.

Results. Of 128 18-month survivors, 15 had severe visual loss attributable to retinopathy of prematurity, 21 had neurodevelopmental deficit, and 5 were deaf. Visual loss was significantly associated with low-peak serum bilirubin concentration (<9.4 mg/dL (<160 μmol/L) versus ≥9.4 mg/dL (odds ratio [OR] confidence interval [CI] 4.48 [1.15–17.43])), low gestational age (OR [CI] per week 1.95 [1.05–3.63]), and longer duration of phototherapy (OR [CI] per 10 hours 1.17 [1.02–1.33]). The association of neurodevelopmental impairment with grades 3 and 4 intraventricular hemorrhage was statistically significant (OR 5.39 [1.83–15.84]), but with high-peak serum bilirubin concentration ≥11.7 mg/dL (≥200 μmol/L), was not significant (OR 2.89 [0.87–9.53]).

Conclusions. In these infants, prolonged phototherapy and low-peak serum bilirubin concentrations were associated with severe visual loss attributable to retinopathy of prematurity. The findings should be interpreted with caution until the evidence is reinforced in other patient populations.