Statistical significance is identified if P<0.05; Pa: P-value for the same group; Pb: P-value from W0 of the two groups; GDM: Gestational diabetes mellitus, Se: Selenium; FPG: Fasting plasma glucose; GPx: Glutathione peroxidase; GRase: Glutathione reductase; CAT: Catalase; SOD: Superoxide dismutase; MDA: Malon dial-dehyde; PC: Carbonyl protein. The gene discussed is CAT; the disease is gestational diabetes.