PFO (Patent foramen ovale)
During fetal development, a baby gets blood and oxygen from the mother through the umbilical cord. A channel between the right and left sides of the heart called the foramen ovale allows the blood from the veins to bypass the lungs. This channel, or hole, normally closes after birth, but in about 25% of people, the foramen ovale doesn’t close completely.¹
When it remains open, it’s called a patent foramen ovale, or a PFO. Typically, a PFO causes no problems at all. However, in some cases, it can allow a blood clot to pass from the right side of the heart to the left side, and this increases the risk of a stroke.