Agenesis of the ductus venosus and its correlation to hydrops fetalis and the fetal hepatic circulation: case reports and review of the literature.
Under normal conditions about 50% of the placental venous return bypasses the liver through the ductus venosus. This blood flow is preferentially directed toward the foramen ovale and provides optimum oxygenation to the fetal heart and brain. Absence of the ductus venosus is a rare vascular anomaly, the significance of which has been disputed. We distinguish the pattern in which the liver is entir