What functions does the foramne ovale serve in fetal circulation?

The foramen ovale is a crucial shunt in fetal circulation that allows blood to bypass the non-functioning fetal lungs. It connects the right atrium to the left atrium, enabling oxygen-rich blood from the placenta to flow directly into systemic circulation. This adaptation helps maintain efficient oxygen delivery to the developing fetus while circumventing the pulmonary circuit, which is not needed until birth. After delivery, the foramen ovale typically closes, transforming into the fossa ovalis as the newborn begins to breathe air and the lungs become functional.