The fetal circulation is based mainly on the veinous circulation during pregnancy. Once the uterine connections are lost, the adult circulation takes over.

In fetal circulation, the placenta provides oxygen and nutrients to the fetus, so the lungs are not used for oxygen exchange - instead, a bypass called the ductus arteriosus shunts blood away from the lungs. After birth, the lungs take over oxygen exchange, the ductus arteriosus closes, and the foramen ovale between the atria closes, redirecting blood flow through the heart to support pulmonary circulation.

The pulmonary circuit is commonly bypassed in fetal circulation. This is because fresh blood is provided by the mother to the fetus.

umbilical cord

To check the fetal circulation you must check the placenta is functioning well as it is the respiratory center for the fetus. You can also check the fetals heart.