Lower plasma melatonin levels in non-hypoxic premature newborns associated with neonatal pain

We analyzed plasma melatonin levels in different groups of preterm newborns without hypoxia and their relationship with several perinatal variables like gestational age or neonatal pain. Prospective cohort study of preterm newborns (PTNB) without perinatal hypoxia, Apgar > 6 at 5 min, and oxygen needs on the third day of life. We compared melatonin levels at day 3 of life in different groups of non-hypoxic preterm infants (Student's t-tests, Mann-Whitney U, and chi