Spiral artery (SpA) remodelling is essential for a successful pregnancy and is best described by its morphological features; vascular smooth muscle cell separation and loss, vessel dilatation, and invasion by extravillous trophoblast cells (EVT). Current opinion holds that EVT fully replace the endothelial cells (EC) of the SpA and take on EC-like characteristics. Placental bed biopsies (6–20 weeks gestation) were immunostained for EC and EVT, showing transient loss of EC. In vessels containing an endovascular EVT plug (n = 28) 77.6 ± 19.3% of the lumen was covered by EC while in vessels without endovascular EVT (n = 100) it was 100 ± 0%. •In early spiral artery remodelling endothelial cells undergo morphological changes.•In the presence of an endovascular extravillous trophoblast cell plug endothelial cells are absent.•Endovascular extravillous trophoblast cells do not take on endothelial cell like characteristics.•Fully remodelled spiral arteries have an intact endothelium.