Women whose migraine headaches produce visual symptoms, referred to as "auras," may be at an increased risk for stroke in comparison to women who do not have migraines, a new study says.

And smoking and oral contraceptives increase this risk, according to a recent report in Stroke: Journal of the American Heart Association.

Women who experienced more recent migraines with aura symptoms (within the last year) are almost seven times more likely to have a stroke compared to women with no history of migraines, said Steven Kittner, M.D., M.P.H., senior author of the study and staff physician at Baltimore Veterans Affairs Medical Center, in a news release.

“Eight percent of stroke cases had onset of probable migraine with visual symptoms in the prior year compared to one percent of controls," he said.

But Kittner said the most "important" finding is that women who have these types of migraines and also smoked and used oral contraceptives had seven times the risk of stroke than women who had just the migraines with visual symptoms alone.

Migraine and stroke share some common risk factors, the researchers said, including high blood pressure and patent foramen ovale (PFO); both have a hereditary basis. While a baby grows in the womb, he or she has a normal opening between the heart’s left and right atria (upper chambers). If this opening doesn’t close naturally soon after the birth, the hole is called PFO.

Migraine also has long been regarded as a risk factor for ischemic stroke, which is a stroke caused by a blot clot blocking blood flow to the brain, the study offered as background.

Researchers analyzed stroke incidence among 386 women 15-to 49-years-old with a first ischemic stroke and 614 women of similar ages and ethnicities who had not had a stroke. Based on their responses to a questionnaire, the women were classified into three categories: having no migraine; probable migraine without visual aura; or probable migraine with visual aura.

Kittner and colleagues also reported that, compared to women with no history of migraine, women with probable migraine with visual symptoms had a 1.5 greater risk of ischemic stroke.

“Young women with probable migraine with visual symptoms can reduce their risk of stroke by stopping smoking and finding alternatives to the use of estrogen-containing contraceptives,” said Kittner, who is also professor of neurology at the University of Maryland School of Medicine and director of the Maryland Stroke Center in Baltimore, Md.

Kittner added that more studies are needed to confirm the findings.