Clinically significant malformations and dysplasias of the fetal blood vessels are unusual and little appreciated. In this chapter we illustrate The vascular pathologies associated with Collagen 4 mutations, Raine syndrome, diffuse medial calcinosis of infancy, Fowler disease, capillary dysplasias such as Fowler disease, cytomegalovirus infection, perivascular amphophilic bodies, as well as hemangiomas and hemangioma-like lesions, dural sinus malformations and angiodysplastic necrotizing encephalopathy.