Fetal circulation. The oxygen pathway from the environment to the fetus is a central concept in fetal monitoring. Before birth, the umbilical vein carries oxygenated and nutrient-Rich blood to the fetal heart, while the umbilical arteries circulate carbon dioxide and waste products back to the placenta. Three shunts are present in Fetal circulation causing blood to flow in a different pathway to an adult: the ductus venosus, the foramen ovale Valley and the ductus arteriosus. The umbilical Vein divides before reaching the liver. One branch called the ductus venosus shunts oxygen-rich blood directly into the vena cava. This oxygen-Rich blood enters the right atrium and the left atrium through the foramen ovale. From the left atrium, the blood flows through the left ventricle into the ascending aorta and on to the head and body. Deoxygenated blood in the right ventricle is pumped into the pulmonary artery that leads to the lungs. The ductus arteriosus diverts blood into the descending Aorta and bypasses the lungs. Some of the blood in the descending Aorta circulates throughout the lower body while the umbilical arteries carry the non-oxygenated blood away from the heart to the placenta.