ENG and fetal growth restriction: Since our longitudinal study on human subjects previously demonstrated that sFlt-1 overexpression is a feature of both term and preterm preeclampsia, while soluble endoglin is overexpressed in cases of IUGR all along pregnancy and also in preterm preeclampsia [64], it is possible that soluble endoglin overexpression in parallel with that of sFlt-1 is a feature needed for the development of early-onset, IUGR-associated preeclampsia, if maternal or environmental factors otherwise do not exaggerate the phenotype of preeclampsia.