en بیوشیمی Biochemistry Research Article Research Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> Hyperbilirubinemia is the most common clinical abnormality in newborns during the first week of life. Phototherapy is the standard treatment but may cause complications, including hypocalcemia, a lesser-known yet significant adverse effect. This study investigated the impact of phototherapy on serum calcium levels in neonates with hyperbilirubinemia.<br> <b>Methods:</b> This observational study was conducted in the NICU of BYL and T.N. Medical College, Mumbai, over 12 months after ethical approval. We included 100 neonates (> 34 weeks gestational age) with hyperbilirubinemia receiving phototherapy. Serum calcium levels were measured before and after phototherapy, and neonates were monitored for clinical hypocalcemia. Data were recorded in a pre-formatted proforma and analyzed using SPSS version 27 (p <0.05 was considered statistically significant).<br> <b>Results:</b> The mean age of neonates was 3&plusmn;1.2 days, the mean gestational age was 37&plusmn;1.2 weeks, and the mean jaundice duration was 2.8&plusmn;1.10 days. Median serum calcium levels decreased significantly from 8.6 mg/dL (8.49-8.61) pre-phototherapy to 7.35 mg/dL (7.33-7.50) post-phototherapy (p <0.001). Hypocalcemia (serum calcium &le;7 mg/dL) occurred in 16% of neonates, with 60% exhibiting mild symptoms like jitteriness or irritability.<br> <b>Conclusion</b>: Phototherapy significantly reduces serum calcium levels in jaundiced neonates, with a notable incidence of hypocalcemia. Clinicians should monitor calcium levels and watch for symptoms during phototherapy to prevent complications. Further studies are needed to establish preventive strategies.</span></span><br> &nbsp;</div> Phototherapy, Infant, Low Birth Weight, Hypocalcemia 15 17 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1710-1&slc_lang=en&sid=1 Mazhar Khan mazharkh91@gmail.com 100319475328460030503 100319475328460030503 No Department of Pediatrics, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, India Akash Sarkate akash.srk175@gmail.com 100319475328460030504 100319475328460030504 No Department of Pediatrics, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, India Poonam Wade poonamwade@gmail.com 100319475328460030505 100319475328460030505 Yes Department of Pediatrics, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, India Sushma Mailk sushmamalik@gmail.com 100319475328460030506 100319475328460030506 No Department of Pediatrics, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, India