Oval Hole

Oval hole

The foramen ovale is an opening that the fetus has between the right and left ventricles of the heart. It allows blood to pass from the right atrium to the aorta, bypassing the lungs.

In the fetus, the lungs do not yet function, so the foramen ovale is necessary to direct blood from the right atrium directly to the aorta. Thus, the blood is saturated with oxygen from the mother’s placenta and distributed throughout the fetus’s body without passing through the lungs.

After the baby is born, the foramen ovale usually closes as the lungs begin to work and oxygenate the blood. However, in some children the foramen ovale does not close completely, causing oxygenated and non-oxygenated blood to mix. This condition is called a patent foramen ovale and may require surgical correction.