Background: In healthy humans, a balance exists between oxygen derived free radical production and their removal by antioxidants. In preterm infants inadequate antioxidant defences may contribute to the pathogenesis of some of the complications of prematurity.

Subjects: 89 samples were collected from 25 infants with median(range) gestational age of 28 weeks (24-40 wk) & birthweight of 1122 g(684-3570 g) to investigate the relationship between plasma total antioxidant status (TAS) and the lipid peroxidation marker malondialdehyde (MDA). 29 infants were studied with median gestation 28 wk (range 22-34 wk) and median bwt 1076 g (600-2150 g) to determine whether low TAS was associated with poor neonatal outcome.

Results: TAS was found to correlate negatively with MDA in plasma during the first 11 days of life (r=-0.24, p<0.03). TAS was significantly related to plasma urate & bilirubin levels, but not to adverse outcomes such as CLD, IVH, ROP or death.

Conclusions: If adverse outcomes are due to inadequate antioxidant defences, these are likely to be intracellular or localised rather than general extracellular deficiencies.