Women who suffer from migraines accompanied by visual disturbances such as flashes of light may be at increased risk of heart attacks and blood clots, researchers said Tuesday.

The study involved 27,860 women, of whom 1,435 had migraine with aura, as such disturbances are called.

Over the course of the 15-year study, there were 1,030 cases of heart attack, stroke or death from a cardiovascular ailment, said the report from the American Academy of Neurology.

"After high blood pressure, migraine with aura was the second strongest single contributor to risk of heart attacks and strokes," said study author Tobias Kurth.

"It came ahead of diabetes, current smoking, obesity, and family history of early heart disease."

Kurth, or Brigham and Women's Hospital in Boston and the French National Institute of Health, is also a fellow of the American Academy of Neurology.

The risk for migraine-plagued women with aura was three times greater than for those with migraines that lacked this disturbance, Kurth told AFP.

A second study released by the same academy said women who had migraines with aura and took hormonal contraceptives were more likely to have blood clots.

Both studies will be presented at the academy's annual meeting in March in San Diego, California