Maternal oxygen supplementation is commonly performed to improve fetal oxygenation and acid-base balance during fetal asphyxia. The efficiency of this treatment is controversial, which may be associated with the production of oxygen free radicals and lipid peroxidation. However, only a few studies have been performed to evaluate these issues. To clarify them, we investigated the effects of maternal oxygen supplementation on fetal oxygenation and lipid peroxidation following fetal asphyxia in late gestation goats.
We measured fetal blood gases, pH and plasma malondialdehyde (MDA), one of the endproducts of lipid peroxidation, before, during and after fetal asphyxia with and without maternal oxygenation in late gestation goats. Fetal asphyxia was induced by a single total umbilical cord occlusion of 3 minutes' duration, and maternal oxygenation was initiated at 20 min before the cord occlusion and terminated at 20 min after the release of cord occlusion.
Maternal oxygen supplementation resulted in a significant increase in fetal PaO₂ before and after the cord occlusion (p<0.05). During the cord occlusion, the extents of hypoxia and acidemia were not changed by maternal oxygen supplementation. Fetal plasma MDA levels before maternal oxygen supplementation averaged 0.80±0.04 μmol/L, significantly increased after the initiation of maternal oxygen supplementation (1.11±0.07 μmol/L), and further increased following fetal asphyxia (1.28±0.06 μmol/L), and after the release of the cord occlusion (1.58±0.7 μmol/L)(p<0.05). These values were significantly higher than those in fetuses without oxygenation. We conclude that maternal oxygen supplementation increased fetal oxygenation but caused a concomitant increase in lipid peroxidation in the fetus.