CAT activity increased in nondiabetes nonpregnant women (2.06 ± 1.86 mU/l) but decreased nonsignificantly (p > 0.05) in gestational diabetes (1.29 ± 0.56 mU/l), normal pregnant (1.28 ± 0.70 mU/l), and diabetes (1.20 ± 1.03 mU/l) women. The gene discussed is CAT; the disease is gestational diabetes.