Aim: To study the incidence of hypocalcemia in neonates with hyperbilirubinemia during phototherapy. Methods: A prospective cross sectional study conducted in pediatric tertiary care hospital. 112 newborns were included in the study and randomized in two equal groups with 56 newborns in each group A(Preterm neonates) and B(Term neonates). Blood samples were drawn from all newborns for measurement of serum ionic calcium, total serum bilirubin and blood group. Total serum bilirubin was measured at the start of phototherapy, 24 hours, 48 hours and then at the end of phototherapy. Serum ionized calcium level was measured at the start of phototherapy and after completion of 48 hours of phototherapy. Results: The mean serum ionic calcium in group A (preterm neonates) and group B (Term neonates) at 0 hrs and 48 hrs after phototherapy was 4.71 mg/dl, 4.14 mg/dl and4.68 mg/dl, 4.34 mg/ dl respectively with a mean difference of 0.57 mg/dl and 0.34 mg/dl with an SD of 0.37and0.24. This decline in serum ionic calcium was statistically significant in both groups. (p< 0.001). On comparing the mean decline in serum ionic calcium after 48 hours of phototherapy in group A and group B was 0.57 ± 0.37 mg/dl and 0.34 ± 0.24mg/ dl respectively. This decline in serum ionic calcium was significantly higher in group A. (p<0.001). Incidence of hypocalcemia found in our study; Group A (Preterm neonates) 26.8% newborns and Group B (Term neonates), 14.3% neonates. Conclusion: There is a significant decrease in serum calcium levels in neonates with receiving phototherapy and more decrease in serum calcium level in preterm neonates compared to term neonates, but difference of hypocalcemia and symptomatic hypocalcemia was not significant.

Keywords: Serum calcium; Hypocalcemia; Hyperbilirubinemia; Phototherapy