If you suffer from migraines your risk of suffering a stroke is double, it is greater still if you suffer from migraines and take birth control pills, say researchers from the Royal Victoria Hospital in Montreal, Canada.

The researchers even went on to say that women who suffer from migraines should not take birth control pills. These women are eight times more likely to suffer from stroke if they go on the pill.

Migraine sufferers who see an aura (bursts of light that cloud their vision) are at elevated risk of getting a stroke (not as high as women who have migraines and are also on the pill).

You can read about this study in the British Medical Journal. The study looked at 14 previous studies and made a compilation of them.

Team leader, Mahyar Etminan, said "This study really strengthens the hypothesis that migraine is an independent risk factor for stroke…………not everyone who has a migraine is going to have a stroke….not at all."

If you do not smoke and are not on the pill, your risk of stroke is still relatively low even if you do have migraines. Your risk is double that of a person who never suffers from migraines - but it is still very low.

Why migraines increase stroke risk is still a mystery. Some experts speculate that as a migraine reduces the flow of blood to the brain, this could make he formation of a clot more likely. Other experts disagree with this theory.

What is a migraine?

A migraine is a very bad headache that tends to recur. With a migraine, you may feel nauseated and might vomit. The pain is usually on one side of your head and you may be very sensitive to bright lights and noises. Moving around can make the headache feel worse. There are many forms of migraine headaches. Classic and common are the two major varieties.

Symptoms of a Migraine

The basic difference between the two types of migraine is the appearance of an "aura." The aura is the occurrence of neurological symptoms 10-30 minutes before the classic migraine attack. You may see flashing lights, zigzag lines or may temporarily lose vision. Other symptoms of classic migraine include speech difficulty, confusion, weakness of an arm or leg and tingling of face or hands.

The pain of a classic migraine headache is described as an intense throbbing or pounding felt in the forehead/temple, ear/jaw or around the eyes. Classic migraine starts on one side of the head but may eventually spread to the other side. An attack may last one to two pain-racked days.

The common migraine - a term that reflects the disorder's more frequent occurrence in the general population - is not preceded by an aura. Some people do experience a variety of vague symptoms before common migraines - mental fuzziness, mood changes, fatigue, and unusual retention of fluid. During the headache phase of a common migraine, you may have abdominal pain and diarrhea, increased urination, nausea and vomiting. Both classic and common migraines can strike as often as several times a week or rarely as once every few years.