The foramen ovale usually closes 6 months to a year after the baby's birth. When the foramen ovale stays open after birth, it's called a patent (PAY-tent, which means "open") foramen ovale (PFO). A PFO usually causes no problems.

Does the foramen ovale close immediately after birth?

Normally, the foramen ovale closes shortly after birth and is subsequently completely sealed off. If the foramen ovale does not seal properly, the condition is called a patent foramen ovale (PFO).

What happens if the foramen ovale does not close?

Rarely, a patent foramen ovale can cause a significant amount of blood to bypass the lungs, causing low blood oxygen levels (hypoxemia). Stroke. Sometimes small blood clots in veins may travel to the heart.