Table 1.

Structure and composition of placental membranes.

Placental membrane	Layers of placental membrane	Extracellular matrix component
Amnion	(1) Epithelium monolayer/amniotic epithelium (2) Basement membrane (3) Compact layer (4) Fibroblast layer (5) Intermediate/spongy layer	Single layer of cells Collagen types III, IV, and V, fibronectin, laminin, and nidogen Collagen types I, III, V, and VI, fibronectin Collagen types I, III, and VI, fibronectin, laminin, and nidogen Collagen types I, III, and IV, proteoglycans
Chorion	(1) Reticular layer (2) Basement membrane (3) Trophoblasts	Collagen types I, III, IV, V, and VI, proteoglycans Collagen type IV, fibronectin, and laminin