Women who get migraine headaches with visual symptoms called "aura" are at a much higher risk for stroke compared to women who do not get migraines, researchers report in the journal Stroke.

Women who smoke, use oral contraceptives, or who recently began suffering from migraines are at an even higher risk.

Dr. Steven Kittner, senior author of the study and staff physician at Baltimore Veterans Affairs Medical Center, looked at 386 women 15 to 49 years old with a first ischemic stroke, a kind of stroke caused by a blot clot blocking blood flow to the brain. They also looked at 614 women of similar ages and ethnicities who had not suffered from a stroke.

Their responses to questions saw the women divided up into three groups: having no migraine; probable migraine without visual symptoms, or probable migraine with visual symptoms.

Migraine sufferers who experience visual symptoms often see flashing lights or zig-zag lines during the debilitating headaches, or they may temporarily lose some of their vision in one or both eyes.

The researchers found that, compared to women with no history of migraine, women with migraine with visual symptoms had a 1.5 greater risk of ischemic stroke.

"Women with recent onset of probable migraine with visual symptoms (within the prior year) were almost seven times more likely to have a stroke compared to women with no history of migraine," said Kittner.

"Second, and probably the most important finding, women who had probable migraine with visual symptoms who also smoked and used oral contraceptives had seven times the risk of stroke than women who had probable migraine with visual symptoms alone."

Kittner notes that the chance that a woman in the 15-to-44-age group will have an ischemic stroke is very low -- one-to-two for every 10,000 people each year.

Nevertheless, he advises those who suffer migraines with visual symptoms should minimize their other stroke risk factors, such as quitting smoking.