Preterm infants are at risk of free radical mediated diseases from oxidative stress (OS) injury. Melatonin (MEL) is a powerful antioxidant and scavenger of free radicals. In preterm neonates, melatonin deficiency has been reported. Several studies tested the efficacy of melatonin to counteract oxidative damage in diseases of newborns such as chronic lung disease, perinatal brain injury, necrotizing enterocolitis, retinopathy of prematurity and sepsis, giving promising results. In these studies, the dosages of melatonin varied over a wide range. The present study was designed to test the hypothesis that oral administration of melatonin reduced OS and consequentially, the occurrence of intraventricular haemorrhage (IVH), necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP) and bronchopulmonary dysplasia (BPD) in preterm newborns.

Inclusion Criteria:

• Gestational age <37 weeks
• Normal liver function tests
• Normal kidney function tests

Exclusion Criteria:

• All babies not born in the clinic
• All babies with severe congenital malformations
• Sepsis
• Inborn errors of metabolism
• Babies suffering from perinatal asphyxia
• Babies born from mothers with mental disorders
• Sample hemolysis
• Insufficient sample
• withdraw informed consent.