Placenta vascular formation is important for fetal growth and development. Proper development of the placenta ensures the exchange of oxygen/nutrients and blood flow necessary for fetal growth. In this chapter, we will discuss the processes of vasculogenesis, angiogenesis, and pseudovasculogenesis during placental development and in pregnancies complicated by intrauterine growth restriction. Some of the factors controlling these processes include oxygen, the VEGF family of growth factors, and their receptors. Disruption in the balance of these controlling factors may explain the vascular malformations seen in pregnancies complicated by intrauterine growth restriction.