Umbilical glutathione levels are higher after vaginal birth than after cesarean section.

Glutathione plays an important role in quenching reactive oxygen species, resulting in oxidation of glutathione, which in times of prolonged oxidative stress may be excreted from the erythrocyte. We investigated arterial and venous umbilical cord levels of glutathione in neonates born by vaginal delivery (n = 140) or cesarean section (n = 38). In a subset of neonates who were delivered vaginally maternal levels were assessed in parallel (n = 14). Median (5th-95th percentile) glutathione levels in venous and arterial umbilical samples were higher after vaginal delivery as compared to cesarean section, 2.7 (0.9-7.3) versus 2.0 (0.6-11.5; P < 0.03) and 3.5 (0.6-22.7) versus 2.3 (0.7-24.3) micromol/L (P < 0.02), respectively. Maternal glutathione levels were higher, 7.8 (4.3-10.6) micromol/L, than corresponding venous (P < 0.001) or arterial (P < 0.02) umbilical levels. These results suggest that vaginal delivery is associated with more oxidative stress than delivery by cesarean section.