Plasma antioxidant capacity in very preterm infants (n=17), measured as the ferric-reducing ability of plasma (FRAP), increased significantly until day 2 postpartum and decreased thereafter until day 7. Within this period, the FRAP values in matched infants, born after impaired placental function (IPF, n=17), did not change. Their FRAP values were lower and the incidence of oxidative stress-related diseases was significantly higher in these infants.