SOD1 and Large for gestational age: Indeed, gestational diabetic women exhibit decreased levels of vitamin E and enhanced concentrations of vitamin C without any changes in vitamin A. Macrosomia also induces decreased levels of vitamin E. GDM and macrosomia are also associated with impaired SOD activities and enhanced levels of serum thiobarbituric acid-reactive substances (TBARSs), suggesting an increased oxidative stress [17].