ENG and preeclampsia: Preeclampsia is attributed to an imbalance of placental-derived circulating pro-angiogenic (vascular endothelial growth factor, VEGF; placental growth factor, PlGF; membrane-bound endoglin, ENG) and anti-angiogenic (soluble fms-like tyrosine kinase 1, sFLT1; soluble endoglin, sENG) [30,70] factors.