The basis of the application of the eNOS KO mice to IUGR research is that the absence of eNOS reduces the capacity of the maternal vascular to accommodate the changes in blood flow necessary for adequate placentation, and that the dams are hypertensive (including with proteinuria) as observed in women with pre-eclampsia, a risk factor for IUGR. This evidence concerns the gene NOS3 and fetal growth restriction.