摘要：Background In newborns, jaundice is the most common ailment that necessitates medical treatment and hospital readmission. The aim of this study was to evaluate vitamin D3 status and investigate the role of phototherapy in the treatment of jaundice and the improvement of vitamin D3 status in neonates with physiological jaundice. Materials and Methods: This prospective research included 50 full-term neonates with physiological hyperbilirubinemia who were phototherapy candidates. They came from Egypt's Qena University Hospitals' Neonatal Intensive Care Units. Colorimetric assays of albumin and ionized calcium, as well as daily serum bilirubin and an ELISA assay of vitamin D3 were performed on the included cases before and 5 days after phototherapy, in addition to clinical assessments. Results: The findings revealed a high prevalence of vitamin D3 deficiency ( 96.7%), and a lower frequency of optimal and insufficient vitamin D3 status (3.3%) with lack of optimal vitamin D3 status among cases. Post-phototherapy total, direct, and indirect bilirubin levels were significantly lower than pre-therapy levels, with substantial improvement in vitamin D3 status (p < 0.05 for all). Furthermore, both serum total bilirubin (r=-0.703, p <0.001) and serum indirect bilirubin (r=-0.710, p <0.001) had significantly negative associations with vitamin D3 serum levels. Conclusion Without vitamin D3 supplementation, neonates with low vitamin D and physiological jaundice who were received phototherapy had considerably improved vitamin D status 5 days later.
