How is a fetal circulatory route different from the systemic or portal circulatory route?

The fetal circulatory route differs from the systemic and portal circulatory routes primarily in its reliance on the placenta for oxygenation and nutrient exchange. In fetal circulation, blood bypasses the lungs and liver through specialized structures like the foramen ovale and ductus arteriOSus, allowing oxygen-rich blood to flow directly from the placenta to the fetus. Additionally, the ductus venosus enables part of the blood to bypass the liver, directing it into the inferior vena cava. This unique circulation is essential for fetal development, as the fetus is not yet breathing air or processing nutrients through its own digestive system.