Rebound Hyperbilirubinemia

\## 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.