Background: Periventricular-intraventricular hemorrhage, necrotizing enterocolitis, chronic lung disease and retinopathy of prematurity have been referred to as oxygen radical diseases (ORD) because they are thought to be related to excess oxidant stress relative to anti-oxidant defenses in premature infants. 8-Isoprostane is a product of lipid peroxidation that can be used as a measure of free radical exposure or injury. The aim of the present study was to determine whether fetal oxidant stress is associated with adverse effects in preterm infants.
Methods: Mothers delivering at gestational age <37 weeks were recruited. Umbilical arterial and venous cord blood samples were collected and 8-isoprostane levels measured. Levels of 8-isoprostane in cord blood were correlated with maternal and perinatal variables, neonatal mortality, and the development of one or more ORD.
Results: Umbilical cord venous, but not arterial, 8-isoprostane levels were associated with mortality and the development of one or more of the ORD. After controlling for gestational age, for each unit change in the log value of 8-isoprostane in venous cord blood the odds of mortality were 12 (95% confidence interval [CI]: 1-223) and oxygen radical disease were 2.7 (95%CI: 1-7.2). Isoprostane levels were not related to gender, method of delivery, use of maternal magnesium or steroids, pregnancy-induced hypertension, or delivery room resuscitation.
Conclusion: Oxidant stress in utero may be an important determinant of mortality and morbidity in preterm infants. Elevated umbilical venous isoprostane levels suggest that oxidative injury to maternal and placental tissues predispose to adverse neonatal outcomes.