ENG and preeclampsia: One of the important evidences is that angiogenic factors produced by the placental tissue are involved in endothelial injury and vasoconstriction, leading to placental dysfunction, such as soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin serum levels are significantly elevated in patients with early-onset preeclampsia (< 34 weeks) [24].