343 Hyperbilirubinemia in a National Cohort of Extremely Premature Infants

Abstract

Background and aims: Hyperbilirubinemia is a possible risk factor for adverse neurodevelopmental outcome in extremely premature infants. The study was undertaken to analyse the frequency, severity and treatment of hyperbilirubinemia in such infants. Methods: Hyperbilirubinemia was studied retrospectively in a national cohort of 422 infants with gestational age (GA) of 220 to 276 completed weeks and/or birth weight (BW) of 500 to 999 g who survived beyond the 2nd day and had bilirubin measured. Group differences were analysed by t-test. Results: Mean maximum bilirubin levels (TsB) were 176±43 µmol/L (range 72-391) and did not differ between GA. TsB ≥ 200 µmol/L and ≥ 250 µmol/L was seen in 24.2 % and 4.3 % of infants, respectively. Mean duration of TsB ≥ 200 µmol/L was 1.9±1.7 days (range 1-10) and did not differ between GA, but was more frequent in boys (p=0.048). 85.4 % of infants received phototherapy for 2.3±1.7 days (range 0-12). One infant received exchange transfusion, blood group immunization was diagnosed in only one infant (AB0). Prenatal steroids caused lower TsB (p=0.003) while initial acidosis increased TsB (p=0.015). Increased TsB was also associated with development of persistent ductus arteriosus (p=0.03), the degree of intraventricular hemorrhage (p=0.015), death (p=0.025), and possible neurologic sequelae at discharge (p=0.02). Conclusions: Significant hyperbilirubinemia is common in extremely premature infants in spite of treatment. TsB seems to be associated with both prenatal and neonatal conditions as well as final outcome. Blood group immunization seems to be significantly underdiagnosed in these infants.