Although the expression of insulin-sensitive GLUT4 on term placenta is low [26], our finding of the down-regulated insulin signal pathway and putative decreased glucose uptake of placenta villi may still have a potential biological significance in the control of transplacental transportation of glucose, and therefore is important in the counteraction of intrauterine hyperglycemia, hyperinsulinemia and macrosomia in GDM pregnancy. This evidence concerns the gene SLC2A4 and hyperinsulinism.