Middle-aged women who have severe migraines with other symptoms are at an increased risk of potentially fatal heart conditions, US researchers say.
Migraine affects many more women than men
Around 10% of those who get migraines have auras, with symptoms such as blind spots or pins and needles in limbs.
The Journal of the American Medical Association study found women who had migraines without aura were not at increased risk.
Experts said more research was needed to establish why there was a link.
There is also concern that all six of the study's authors have done consulting work or received research funding from makers of treatments for migraines or heart-related problems.
The authors said they did not report their financial ties because they did not believe they were relevant to the study.
Migraine can affect people at any age but it is most prevalent between the ages of 20 and 50 and two thirds of sufferers are women. The condition can run in families.
Previous research had shown migraines with aura were linked with strokes caused by blood clots.
There have also been indications it is linked to an increase in cardiovascular risk, but this had not been conclusively proved.
In this study, researchers from Brigham and Women's Hospital and the Harvard School of Public Health in Boston, studied 27,840 women aged 45 or older for 10 years from the early 1990s.
At the beginning of the study, 5,125 women (18.4%) reported that they had a history of migraine.
Of the 3,610 who had experienced migraine in the previous year, just under 40% reported aura symptoms.
During the course of the study, there were 580 major cardiovascular events such as heart attack, stroke and angina. There were 130 deaths from cardiovascular disease.
Women who currently experienced migraine with aura had a significantly increased risk of stroke, heart attack, other serious heart conditions and death from CVD caused by narrowed arteries.
When age was taken into account, there were 18 additional CVD events which could be directly linked to migraine with aura per 10,000 women per year.
Dr Tobias Kirth, who led the study, said: "Since migraine without aura is far more common than migraine with aura, our data demonstrate no increased risk of CVD for the majority of migraine patients.
"Future research should focus on a better understanding of the relationship between migraine, aura status, and cardiovascular event."
In an editorial in JAMA, Dr Richard Lipton and Dr Marcelo Bigal, from the Albert Einstein College of Medicine said the same genetic flaw - linked to a increased levels of homocysteine - an amino acid in the blood - is seen in CVD and migraine with aura - but not in migraine without aura.
They added: "For patients with migraine with aura, clinicians should have heightened vigilance for modifiable cardiovascular risk factors, such as high blood pressure, high cholesterol, and smoking."
The doctors said further research would be needed to determine if migraine with aura was itself a modifiable risk factor for CVD, and if medicines to prevent migraine might cut CVD risk.
Ellen Mason, a cardiac nurse at the British Heart Foundation, said: "Female migraine sufferers need not be alarmed by this study.
"However, it does highlight the need for further scientific research into why migraine sufferers who experience an aura are at increased risk of cardiovascular disease."
She added: "It would be wise for women who experience migraines with aura to keep their lifestyles as healthy as possible to try to offset any small increase in risk from heart disease due to migraine."
A spokeswoman for the Migraine Association, said: "The results of this study are interesting.
"Migraine is such a complex neurological condition that the more we can understand from research such as this, the better equipped sufferers can be, as well as healthcare professionals, when it comes to preventative treatment options and lifestyle considerations."