The associations between labor and delivery mode and maternal and placental oxidative stress.

To study oxidative stress differences between women with normal vaginal deliveries (VD) and those with elective cesarean sections without labor (CS), total antioxidant capacity (TAC), erythrocyte glutathione peroxidase (GPX) and superoxide dismutase (SOD) activity, 8-isoprostane, nitrotyrosine and 8-hydroxydeoxyguanosine (8-OHdG) in blood, urine, and placental samples were assessed. The VD group had significantly higher placental 8-isoprostane and 8-OHdG levels as well as greater plasma TAC and 8-OHdG levels and lower erythrocyte SOD activity in umbilical venous blood. Women with VD exhibited differential changes in maternal oxidative stress before and after delivery compared with women with CS. Furthermore, we found that repetitive hypoxia-reoxygenation increased the 8-isoprostane and 8-OHdG levels in villous explants compared with the normoxic controls. Together, these results indicate that labor is associated with increased placental oxidative stress and has an influence on maternal oxidative stress. Therefore, women with VD exhibit different oxidative stress indicators than do those with CS.