The effect of phototherapy treatment on serum melatonin levels in term newborns

Background/aim: The aim of this study was to investigate the effect of phototherapy treatment on serum melatonin levels in term newborn infants. Material and methods: This study was planned as a single-center, prospective, observational, case-control study. Term infants (gestation week >= 37 weeks) who received at least 6 h of phototherapy due to jaundice constitute the phototherapy group, while the term infants without jaundice and who were exclusively breastfed constitute the control group. Melatonin levels were examined by taking blood samples from babies in both groups at 02:00 at night. Melatonin values were compared between groups. The effect of phototherapy on serum melatonin levels was investigated. The relationship between the duration of phototherapy and maximum serum bilirubin values on melatonin values was investigated. Results: Seventy term infants (64.3% girls) were included in the study. Mean gestational week was 38.3 +/- 1.1 weeks, mean birth weight was 3295 +/- 434 g. There was no statistically significant difference between the phototherapy group and the control group in terms of sex, type of delivery, gestational week, birth weight, height, and head circumference (all p > 0.05). Serum melatonin level was 20.3 +/- 5.9 pg/mL (range: 8.7-36.6 pg/mL) in the phototherapy group and 19.9 +/- 4.38 pg/mL (range: 9.9-26.3 pg/mL) in the control group. There was no significant difference between the two groups in terms of serum melatonin levels (p = 0.155). The mean total bilirubin value was 17.65 +/- 1.48 mg/dL, and the average duration of phototherapy application was 13.94 +/- 7.64 h in the babies in the phototherapy group. No correlation was found between the duration of phototherapy application and serum melatonin levels (p = 0.791). Conclusion: It was determined that there was no significant difference in serum melatonin levels in term newborn babies who received phototherapy for at least 6 h due to jaundice. No correlation was found between the duration of phototherapy application and the serum melatonin level of the maximum bilirubin values.