Morphofunctional study of umbilical cords from pregnancies complicated by preeclampsia shows both activation and lesion of endothelium. The cellular findings in umbilical cords from pregnancies complicated by preeclampsia can be summarized as: (i) higher number of cells with secretion bladders and increase in the number and size of both secretion bladders and microvilli-like protrusions; (ii) increase in collagen, fibrin, fibronectin and lipidic vesicles in the vessel wall; (iii) vacuolization of endothelial cells; (iv) presence of lipidic vacuoles and lipophages in the vessel wall; (v) erosion and disorganisation of the endothelium that exposes extracellular proteins to the blood flow. Endothelial cell cultures from preeclamptic pregnancies show kinetic disorders and cell detachment. The results confirm that an endothelial cell lesion occurs in preeclampsia and this cellular disorder can be reproduced in vitro.