Rebound Hyperbilirubinemia Study

Predictors of Rebound Hyperbilirubinemia After Phototherapy in Neonates

## 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.

Study Overview

• Status: Not yet recruiting
• Conditions: Neonatal Hyperbilirubinemia; Rebound Hyperbilirubinemia

Detailed Description

## 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.

• Study Type: Observational
• Enrollment (Estimated): 300

Contacts and Locations

• Study Contact: Name: Dilek Kurnaz, M.D; Phone Number: +905556119280; Email: drdilekkurnaz@gmail.com

Study Locations

• Turkey (Türkiye)
  • Sultangazi
    • Istanbul, Sultangazi, Turkey (Türkiye), 34265
      • University of Health Sciences, Haseki Training and Research Hospital
      • Contact: Dilek Kurnaz, M.D; Phone Number: 05556119280; Email: drdilekkurnaz@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of neonates admitted to the NICU for neonatal hyperbilirubinemia and treated with phototherapy according to institutional protocols and current guideline-based phototherapy thresholds. Both standard and intensive phototherapy modalities may be used based on bilirubin levels, gestational age, and neurotoxicity risk factors.

Eligible neonates will be prospectively followed after discontinuation of phototherapy for evaluation of rebound hyperbilirubinemia and repeat phototherapy requirement. Clinical, laboratory, hemolytic, feeding-related, and phototherapy-related variables will be recorded and analyzed to identify predictors of clinically significant rebound hyperbilirubinemia.

Description

Inclusion Criteria:

• Neonates admitted to the NICU with neonatal hyperbilirubinemia Gestational age ≥35 weeks Requirement for phototherapy according to institutional protocol and current guideline-based phototherapy thresholds Receipt of standard and/or intensive phototherapy Availability of bilirubin measurements before, during, and after phototherapy Availability of rebound bilirubin measurement within 48 hours after phototherapy discontinuation Written informed consent obtained from parents or legal guardians, if required by the ethics committee

Exclusion Criteria:

• Major congenital anomalies Conjugated hyperbilirubinemia Neonates requiring exchange transfusion before completion of initial phototherapy Severe perinatal asphyxia Proven or suspected inborn errors of metabolism affecting bilirubin metabolism Significant congenital liver disease Neonates transferred to another center before completion of rebound bilirubin follow-up Missing or incomplete clinical or laboratory data Absence of rebound bilirubin measurement within 48 hours after phototherapy discontinuation Parents or legal guardians declining participation, if consent is required

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Neonates Receiving Phototherapy; This cohort includes neonates admitted to the NICU and treated with phototherapy for neonatal hyperbilirubinemia according to current institutional protocols and guideline-based phototherapy thresholds. Both standard and intensive phototherapy modalities may be used depending on bilirubin levels, gestational age, and neurotoxicity risk factors. Phototherapy is administered using Astek phototherapy devices and/or tunnel phototherapy systems, either as single-device or double-device therapy. Irradiance intensity may be adjusted according to clinical severity. Phototherapy is applied continuously except during feeding and routine care intervals. Serum bilirubin levels are monitored during and after phototherapy according to unit protocol. Rebound bilirubin measurements are routinely obtained after discontinuation of phototherapy, and additional measurements are performed in neonates considered at increased risk for rebound hyperbilirubinemia. Clinical, labo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinically Significant Rebound Hyperbilirubinemia Requiring Repeat Phototherapy	Clinically significant rebound hyperbilirubinemia is defined as an increase in total serum bilirubin after discontinuation of initial phototherapy that reaches the guideline-based phototherapy threshold and requires initiation of repeat phototherapy.	Within 48 hours after phototherapy discontinuation

Collaborators and Investigators

• Sponsor: Haseki Training and Research Hospital

Publications and helpful links

General Publications

• Donneborg ML, Thorsteinsson K, Bruun NH, Ebbesen F. Short-time intensive phototherapy of hyperbilirubinemic neonates: efficacy, bilirubin rebound and risk factors for rebound. Pediatr Res. 2026 Feb 28. doi: 10.1038/s41390-026-04870-3. Online ahead of print.

Helpful Links

• ## Prospective study evaluating risk factors and bilirubin rebound after discontinuation of phototherapy in neonates.

Study record dates

Study Major Dates

• Study Start (Estimated): June 15, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): November 1, 2026

Study Registration Dates

• First Submitted: July 3, 2026
• First Submitted That Met QC Criteria: July 3, 2026
• First Posted (Actual): July 10, 2026

Study Record Updates

• Last Update Posted (Actual): July 10, 2026
• Last Update Submitted That Met QC Criteria: July 3, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Neonate; Phototherapy; Neonatal Jaundice; Rebound Hyperbilirubinemia; Repeat Phototherapy
• Additional Relevant MeSH Terms: Pathologic Processes; Infant, Newborn, Diseases; Hyperbilirubinemia; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Pathological Conditions, Signs and Symptoms; Jaundice, Neonatal; Hyperbilirubinemia, Neonatal
• Other Study ID Numbers: HASEKI-NICU-RHB-2026-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be publicly shared because the study involves sensitive neonatal clinical data obtained from a single-center NICU cohort. Data sharing may be restricted by institutional policies and ethical considerations regarding patient confidentiality and privacy. Aggregated and anonymized study results will be presented in scientific publications and presentations.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No