Many studies suggested that intrauterine hyperglycemia may increase maternal supply of carbohydrates leading to fetal hyperinsulinemia, and stimulation of the insulin sensitive tissue by hyperinsulinemia results in increased fetal growth [5,6], but the exact mechanism of macrosomia induced by intrauterine hyperglycemia environment of GDM is still not completely understood. The gene discussed is INS; the disease is Hyperinsulinemia.