They measured mitochondrial enzyme activity and markers of oxidative stress (respiratory chain enzyme complexes I, II, III, and IV; citrate synthase (CS), aconitase, MnSOD and catalase, GSH:GSSG) in skeletal muscle tissue from pregnant women of normal weight (NW), obese pregnant women with normal glucose tolerance (NGT), and obese pregnant women with GDM, undergoing cesarean delivery (about 37 week gestation). This evidence concerns the gene CS and gestational diabetes.