Evaluation of the Predictive Value of Umbilical Cord Serum Bilirubin Level for the Development of Subsequent Hyperbilirubinemia in Term and LatePreterm Neonates

Background: Considering the increasing rates of early hospital discharge and kernicterus in healthy full term newborns, timely identification of neonates at risk of severe hyperbilirubinemia is of great significance. The aim of this study was to investigate the predictive value of umbilical cord serum (UCS) bilirubin level for subsequent hyperbilirubinemia. Moreover, we compared the predictive value of UCS bilirubin with that of risk factor assessment and predischarge bilirubin level. Methods: In this prospective, cohort study, 450 healthy neonates born at the gestational age of  35 weeks were included. UCS bilirubin concentration, direct Coombs test results, and blood group were determined in the newborns. Total serum bilirubin level was re-assessed before hospital discharge. The subjects were followed-up for 1-4 days after discharge and the total serum bilirubin level was measured in neonates with clinical jaundice. Results of the assessment of risk factors for hyperbilirubinemia were recorded. Results: In total, 319 newborns were followed-up within the study period. The mean UCS bilirubin level in non-icteric and icteric neonates was 2.35 and 2.49 mg/dl, respectively. No significant relationship was found between UCS bilirubin level and development of hyperbilirubinemia (P=0.30), whereas a significant correlation was detected between predischarge bilirubin level and development of jaundice (P=0.009). Gestational age, birth weight, history of jaundice in siblings, and mode of delivery were the clinical risk factors which showed a significant correlation with postnatal hyperbilirubinemia. Conclusion: Based on the findings, UCS bilirubin level could not predict subsequent hyperbilirubinemia. Therefore, the best predictive marker for neonatal jaundice is the assessment of clinical risk factors and predischarge bilirubin level.