The foramen ovale is a hole that communicates the right side with the left side of the heart. During pregnancy, it is this communication that enables the fetus to receive its mother's oxygenated blood to develop since its lungs still do not function. Soon after birth, there is the natural closure of the foramen ovale. However, in a minority of people this natural closure does not occur and the foramen ovale remains open, ie patent, throughout life.
