Association Between Serum Calcium and Unconjugated Hyperbilirubinemia in Neonates Receiving Phototherapy: A Prevalence Study

Abstract

Introduction and Objectives- Neonatal hyperbilirubinemia is a frequent condition observed in the first week of life, affecting up to 80% of newborns. It presents as jaundice due to elevated levels of bilirubin, often resulting from the immature liver’s inability to process the rapid breakdown of red blood cells. To assess the impact of phototherapy on serum calcium levels in term and preterm neonates with unconjugated hyperbilirubinemia. Materials and Methods- This hospital-based, observational cross-sectional study was conducted over 12 months in the Neonatal Intensive Care Unit (NICU), Department of Paediatrics. A total of 107 neonates—both term and late preterm—requiring phototherapy for unconjugated hyperbilirubinemia, were enrolled using purposive sampling. Eligible neonates were otherwise healthy, and those with conditions like sepsis, congenital anomalies, or prior hypocalcemia were excluded to minimize confounding factors. Blood samples were collected before and after phototherapy to assess total and ionized calcium levels. Serum bilirubin was measured using the Diazo method, while calcium levels were analyzed using the Arsenazo III method and ion-selective electrode technology. Data were statistically analyzed using SPSS ver.27, with significance set at p<0.05. Results- Among the 107 neonates receiving phototherapy for unconjugated hyperbilirubinemia, 54.2% were preterm and 45.8% were term. Hypocalcemia was observed in 78 neonates (72.9%), with a significantly higher prevalence in preterm infants (64.2%) compared to term infants (35.8%). A significant association was found between the duration of phototherapy and serum calcium levels; 91.1% of hypocalcemic neonates had received phototherapy for more than 24 hours (p=0.004). Double surface phototherapy was used in 68.3% of cases, and 57% of neonates required treatment beyond 24 hours. Conclusion- Phototherapy is a cornerstone in the treatment of neonatal jaundice, but its association with hypocalcemia—particularly in preterm infants and with extended exposure—highlights the need for routine calcium monitoring. Early identification and management of hypocalcemia are crucial to prevent adverse outcomes. Clinical protocols should consider baseline calcium screening and follow-up in neonates undergoing prolonged or intensive phototherapy to enhance safety and improve overall neonatal care outcomes.