Some studies have found that patent foramen ovales (PFOs) are more common in people with unexplained strokes and migraines with aura. PFO could be a cause or coincidence of stroke.Patent foramen ovale (PFO) or hole in the heart, affects millions of people and can cause a stroke. If you have a PFO and low blood oxygen levels or an unexplained stroke, you may need a procedure to close the hole. This does not mean that everyone who has PFO will experience a stroke or mini-stroke. In a paradoxical stroke, a blood clot that develops in a vein (often leg veins) breaks free and travels to the right side of the heart. Atrial fibrillation and patent foramen ovale are both associated with an increased risk of ischemic stroke. A baby's lungs are not used when it grows in the womb, so the hole does not cause problems in an unborn infant. Most PFOs cause no symptoms or complications. Larger PFOs may cause stroke.