ST. LOUIS, Jan. 11 (UPI) -- Some people with migraines may be able to trace their problem to a hole in the heart that formed before birth, say U.S researchers.
According to lead author John Lasala at the Washington University in St. Louis, the hole is between the two top chambers of the heart, is the size of a pencil eraser, and is called a patent foramen ovale or PFO.
Babies in the womb have PFOs, which allow the blood to circulate without going to the lungs, since the lungs don't function until after birth.
Once the baby is born, the PFO usually closes, but in a quarter of the population, the hole stays partially open. This means that blood can go directly from the right to the left atrium and back out to the body without going to the lungs for filtering and oxygenation.
"We think that something usually cleared out by the lungs is in that blood and can trigger migraines," said Lasala.
In British trials, 37 percent of people with PFOs and migraines got relief from their headaches after surgery closed their PFOs. Now 13 U.S. medical centers, led by St. Jude Medical in Minnetonka, Minn. and including Washington University School of Medicine, are trying to duplicate those results.
"We don't believe this will be a cure for all migraines," Lasala said, "but even if it's effective in just 50 percent of migraine patients with PFOs, it could benefit a lot of people."