“…Successful placentation and embryonic/fetal growth and development are dependent upon optimal vascularization of the villous placenta (Kingdom et al , 2000; Reynolds et al , 2005; Torry et al , 2002; Wulff et al , 2003), and thus a deficiency in placental villous vascularization has been associated with spontaneous abortion and embryonic death (Shore et al , 1997). Development of the vascular system within the placental villous stroma is initiated by in situ differentiation of endothelial cells from fetal mesenchymal precursors or angioblasts, i.e.…”