Statistical significance is identified if P<0.05; Pa: P-value for healthy pregnant women and Se-supplemented women with GDM groups; Pb: P-value for Se-supplemented and non-supplemented women with GDM groups; GDM: Gestational diabetes mellitus; Se: Selenium; FPG: Fasting plasma glucose; GPx: Glutathione peroxidase; GRase: Glutathione reductase; CAT: Catalase; SOD: Superoxide dismutase; MDA: Malondialdehyde; PC: Carbonyl protein. The gene discussed is SOD1; the disease is gestational diabetes.