Association Between Birth Weight and Severity of Neonatal Jaundice: A Case-Control Study.

Background Neonatal jaundice (NNJ) is a common condition among newborns worldwide, with some cases progressing to severe hyperbilirubinemia and serious neurological complications. Identifying high-risk infants is critical for early intervention. While low birth weight (LBW) is widely recognized as a potential risk factor due to immature liver function and feeding issues, the association between macrosomia and NNJ remains unclear. Given regional variations in risk factors, this study aimed to assess the relationship between birth weight categories and the severity of NNJ in neonates admitted to Ibn Al-Balady Hospital in Baghdad, Iraq. The hypothesis was that LBW infants are at a higher risk of developing severe jaundice compared to those with normal birth weight. Objective To investigate the association between birth weight categories and the severity of neonatal jaundice among infants admitted to Ibn Al-Balady Hospital of Children and Maternity in Baghdad, Iraq. Methods A retrospective case-control study was conducted at Ibn Al-Balady Hospital in Baghdad from May 2 to June 22, 2025. Cases included neonates (≤28 days) diagnosed with severe neonatal jaundice requiring phototherapy or exchange transfusion, while controls were neonates without severe jaundice, matched at a 2:1 ratio. Data were extracted from medical records using a standardized form and included birth weight, gestational age, mode of delivery, maternal factors, and bilirubin levels. Birth weight was categorized as LBW (<2500 g), NBW (2500-3999 g), and macrosomia (≥4000 g). Statistical analysis involved chi-square tests, t-tests, and multivariate logistic regression to assess associations between birth weight and severe NNJ, adjusting for confounders like gestational age. Ethical approval was obtained, and patient confidentiality was maintained. Results A total of 152 cases with severe NNJ and 305 controls were included. The proportion of low birth weight infants was significantly higher in the severe jaundice group compared to controls (25.7% vs. 9.2%, p<0.001). After adjusting for gestational age, low birth weight was significantly associated with increased odds of severe NNJ [adjusted odds ratio (AOR)=2.78, 95% confidence interval (CI): 1.59-4.86, p<0.001]. No significant association was found between macrosomia and severe NNJ (Adjusted OR=1.15, 95% CI: 0.48-2.77, p=0.75). Conclusion Preterm birth and low birth weight are major risk factors for severe neonatal jaundice. Early identification and close monitoring of high-risk infants are crucial to prevent complications. Establishing national guidelines in Iraq would help standardize care and improve outcomes for affected newborns.