Predictors of Rebound Hyperbilirubinemia Study

Overview

\## Brief Summary Neonatal hyperbilirubinemia is one of the most common causes of neonatal hospitalization and phototherapy treatment. Although phototherapy is highly effective, rebound hyperbilirubinemia following discontinuation of phototherapy may occur in some infants and may require repeat treatment. Early identification of neonates at risk for clinically significant rebound hyperbilirubinemia could help optimize discharge timing and reduce unnecessary hospital stay and repeat bilirubin testing. This prospective observational study aims to evaluate the predictors of rebound hyperbilirubinemia after phototherapy discontinuation in neonates admitted to the NICU. Particular focus will be placed on the role of delta total serum bilirubin (ΔTSB), defined as the difference between the phototherapy threshold and the measured bilirubin level at the time of phototherapy discontinuation. Clinical, demographic, laboratory, hemolytic, feeding-related, and phototherapy-related variables will also be analyzed. The primary outcome will be clinically significant rebound hyperbilirubinemia requiring repeat phototherapy within 24-48 hours after discontinuation of the initial phototherapy treatment. Secondary outcomes include rebound bilirubin levels, duration of hospitalization, and factors associated with repeat phototherapy.

\## Detailed Description Neonatal hyperbilirubinemia remains one of the leading causes of neonatal hospitalization worldwide. Phototherapy is the standard treatment for significant unconjugated hyperbilirubinemia and is highly effective in reducing serum bilirubin levels. However, a subset of neonates may develop rebound hyperbilirubinemia after discontinuation of phototherapy, occasionally requiring repeat phototherapy and prolonged hospitalization. Current evidence regarding predictors of rebound hyperbilirubinemia remains limited, particularly in prospective NICU-based cohorts. Identification of infants at increased risk for clinically significant rebound hyperbilirubinemia may improve individualized monitoring strategies, optimize timing of discharge, and reduce unnecessary bilirubin measurements and hospital stay. This prospective observational study will include neonates admitted to the NICU and treated with phototherapy for hyperbilirubinemia. Clinical and laboratory parameters associated with rebound hyperbilirubinemia will be evaluated. Special emphasis will be placed on delta total serum bilirubin (ΔTSB), defined as the difference between the phototherapy threshold recommended by current guidelines and the measured total serum bilirubin level at the time of phototherapy discontinuation. Additional variables including gestational age, postnatal age at phototherapy initiation, feeding type, hemolytic risk factors, bilirubin kinetics, and phototherapy characteristics will also be analyzed. Rebound bilirubin measurements will be obtained within 24-48 hours after discontinuation of phototherapy according to unit protocol. The primary objective is to determine predictors of clinically significant rebound hyperbilirubinemia requiring repeat phototherapy. Secondary objectives include evaluation of bilirubin rebound levels, hospitalization duration, and the association between phototherapy characteristics and rebound risk.