Assessment of Changes in Serum Calcium Among Neonates Undergoing Phototherapy for Jaundice

Background: Neonatal jaundice is a common condition requiring phototherapy, which, while effective in reducing bilirubin levels, may lead to hypocalcaemia. The decline in serum calcium during phototherapy is often overlooked in routine neonatal care, particularly in resource-limited settings. Methods: This prospective observational study included 100 term and late preterm neonates requiring phototherapy based on AAP 2004 criteria. Total and ionized serum calcium levels were measured before and after phototherapy. Clinical characteristics, bilirubin levels, duration of phototherapy, and incidence of hypocalcaemia were analysed using IBM SPSS version 26.0. A p-value <0.05 was considered statistically significant. Results: The mean total serum calcium significantly decreased from 9.30 ± 0.45 mg/dL to 8.55 ± 0.50 mg/dL after phototherapy (p < 0.001). Ionized calcium also declined significantly from 4.80 ± 0.25 mg/dL to 4.40 ± 0.30 mg/dL (p < 0.001). Overall, hypocalcaemia (<8 mg/dL) was observed in 18% of neonates. Late preterm infants showed a higher incidence (28.6%) compared to term neonates (13.9%). Longer phototherapy duration was strongly associated with hypocalcaemia—7.4% (<24 hours), 26.3% (24–48 hours), and 50% (>48 hours). Conclusion: Phototherapy causes a significant reduction in both total and ionized serum calcium, with nearly one-fifth of treated neonates developing hypocalcaemia. Preterm infants and those receiving prolonged phototherapy are particularly vulnerable. Routine monitoring of calcium levels during phototherapy is recommended to prevent complications and improve neonatal outcomes. Keywords: Neonatal jaundice; Phototherapy; Serum calcium; Hypocalcemia; Ionized calcium; Hyperbilirubinemia;