Aim The diseases of newborns which involve oxidative stress are: respiratory distress (RDS), bronchopulmonary dysplasia, retinopathy and necrotizing enterocolitis. The aim of the study was to evaluate the oxidative stress trough the lipid peroxidation at preterm newborns with RDS.

Material and methods We conducted a prospective, non –randomised study. The study group was represented by sixty preterm newborns with RDS. The control was represented by 20 healthy late preterm newborns. For all patients family’s consent was obtained. The study of the oxidative stress was performed by the measurement of malonildyaldehide (MDA) by Satoh’s method. For each newborn we determined the MDA on the first and third day of life. For the control was carried out one determination on the first day of life. The statistical analysis was done using the SPSS program.

Results The RDS was present in mild form at 35% newborns, medium form at 42% and severe form at 23%. Seven newborns presented neonatal septicemia. Cerebral haemorrhage was present at 12 newborns of the study group. At 13 preterm the RDS was treated with mechanical ventilation. The MDA was higher at the neonates with the above circumstances. On the first day of life the MDA value was higher than on third day at the control. Also the MDA was significantly higher on the study group than at the control.

Conclusion The RDS at preterm is a significant risk factor for oxidative stress. The association of other diseases to RDS will increase the oxidative stress.