ASSESSMENT OF PHOTOTHERAPY-INDUCED HYPOCALCEMIA AND ITS CORRELATION WITH URINARY CALCIUM EXCRETION IN TERM AND PRETERM NEWBORNS WITH NEONATAL HYPERBILIRUBINEMIA: A CROSS-SECTIONAL STUDY WITH CONTROLS

Introduction: Although hypocalcemia is often proposed to be associated with phototherapy in both term and preterm newborns,its exact incidence, clinical significance, and underlying mechanism still remain to be elucidated. Objective: The objectiveof this study was to determine the prevalence of hypocalcemia and its etiopathogenesis in terms of urinary calcium excretion.Methods: This study was carried out in a tertiary care center in North India with 50 neonates (29 term and 21 preterm) in thetest group receiving single surface phototherapy. The other 50 age, sex, and gestational age-matched neonates were taken ascontrols who did not receive phototherapy. Serum calcium levels at 0 and 48 h and urinary calcium/creatinine ratio (mg/mg) at0 and 24 h of starting phototherapy were determined in both the groups and compared. Results: Total 12 preterm (57.1%) and9 term newborns (31%) developed hypocalcemia after 48 h of phototherapy. The mean difference of serum ionized calciumbetween two groups was statistically significant at 48 h (4.58 mg/dl in the test group vs. 4.94 mg/dl in the control group,p<0.001). Percentage change in mean of urinary calcium/creatinine ratio at 24 h from baseline was 1.39% in the controlgroup while it was 60.7% in the test group with statistically significant difference (p<0.001) between two groups. Only aweak negative correlation between serum ionized calcium and urinary calcium/creatinine ratio with correlation coefficientr=−0.316 could be established in the study among both term and preterm neonates. Conclusion: Both preterm and termneonates undergoing phototherapy are at increased risk for hypocalcemia and increased urinary calcium excretion. A universalrecommendation regarding calcium supplementation in neonates undergoing phototherapy is yet to be established but seemslike a reasonable intervention.