PGF and preeclampsia: It has been hypothesized that both the reduction in circulating placental growth factor (PlGF) and the elevation of the antiangiogenic protein soluble fms-like tryosine kinase 1 [sFLT1; the soluble decoy receptor for PlGF and vascular endothelial growth factor (VEGF)]—that arise before clinically evident preeclampsia—are manifestations of syncytiotrophoblast cellular stress or syncytiotrophoblast dysfunction [41].