Hospitalization Rates for Phototherapy in Neonates With Transcutaneous Bilirubin (TcB) Values >5.5 mg/dL Below the Phototherapy Threshold

Introduction: Neonatal jaundice (hyperbilirubinemia) affects over half of term infants. Although most cases are benign, some progress to severe hyperbilirubinemia, causing acute bilirubin encephalopathy or kernicterus. Early detection is essential. Total serum bilirubin (TSB) is the diagnostic standard, but invasive. Transcutaneous bilirubin (TcB) provides a reliable non-invasive screening tool. The 2022 American Academy of Pediatrics (AAP) guidelines define phototherapy thresholds but do not specify safe discharge bilirubin margins. Understanding outcomes for infants discharged near, but below, these thresholds may help guide follow-up and reduce readmissions. Objective: To evaluate hospitalization rates for phototherapy among neonates discharged with TcB values >5.5 mg/dL versus ≤5.5 mg/dL below the AAP phototherapy threshold and assess associations with ethnicity and feeding type. Design/methods: A retrospective cohort study of 1,848 term and near-term infants discharged from a single birth center (September 2022-September 2024) was conducted. The difference between TcB and the AAP phototherapy threshold was calculated, and infants were categorized as >5.5 mg/dL or ≤5.5 mg/dL below the threshold. The primary outcome was rehospitalization for phototherapy within one week. Analyses included chi-square and t-tests. Results: Among 1,848 infants, 46 (2.5%) were rehospitalized for phototherapy. Rehospitalization occurred in 7.9% of infants discharged ≤5.5 mg/dL below threshold compared with 1.2% of those >5.5 mg/dL below (χ²=53.0, p<0.001). Infants discharged closer to the threshold were nearly seven times more likely to be readmitted. Asian and Hispanic infants had higher bilirubin levels and readmission rates (p<0.05). Exclusive breastfeeding showed a trend toward higher rehospitalization rates (3.3%) than formula (1.4%) or mixed feeding (1.6%) (p=0.061). Conclusion: Infants discharged within 5.5 mg/dL of the phototherapy threshold have a significantly higher risk of rehospitalization for phototherapy. Ethnicity and feeding type may influence risk. Maintaining a discharge margin >5.5 mg/dL and ensuring closer follow-up for higher-risk groups may reduce preventable readmissions and improve management of neonatal jaundice.