Nineteenth-century medicine may have given us life-saving leaps forward in vaccination and sterilisation, but it was still tainted with more than a hint of quackery - and misogyny.

When treating a woman suffering from migraines, the medicine men of the era recommended that she have sex with her husband. Why? In the Victorian medical mind, it stood to reason that, as more women had migraines than men, the headaches had to be a hysterical condition related to that most devious and unpredictable of organs, the womb.

Time and medicine may have moved on, but for migraine sufferers, the pain continues - as does the debate over what causes them, what other illnesses they might be linked to, and how best to treat them. And the suffering of those who have to live with migraines is not always eased by the acres of newsprint speculating about the connections between the nausea-ridden headaches and everything from brain tumours to "sticky blood" syndrome.

Yesterday, new research emerged suggesting that thousands of people who have migraine with aura - a sick headache accompanied by zigzagging lines in the vision - may also have holes in the heart. After studying the cardiac procedures used to treat stroke patients and divers with the bends, a team of researchers is trying to find out whether people who have migraine with aura also have a common heart defect called patent foramen ovale, or PFO. Doctors discovered that divers and stroke patients who have migraine with aura have found their headaches cured after their PFO was repaired by surgery.

Comforting though this sounds, it could give some people with migraines another factor to add to the list that they already worry about.

Dr Andrew Dowson, director of the headache service at Kings College, London, says that trials into the PFO-migraine link could be "the most significant treatment for over a decade". Even so, their benefit may only be limited. Although 10% of people are thought to suffer migraines, only about 15% of them have migraine with aura, and many of those people will not have PFOs.

"We've always known that hole-in-the-heart could be associated with migraines with aura," says Dr E Anne MacGregor, director of clinical research at the City of London Migraine Clinic. "Still, a lot of people can have a hole in the heart thatdoesn't cause them migraines, and a lot of people with migraines don't have holes in their hearts. So it only affects a small proportion of people."

Such caution is typical among migraine experts. Confronted on a daily basis with people who fear they may be about to have a stroke, or are incubating a brain tumour, the specialists' watchwords are common sense and reassurance.

"Migraine is not a life-threatening condition," says Ann Turner, director of the Migraine Action Association. "If you look behind the scaremongering headlines, you often find that the studies on which the information is based are very small - sometimes as few as 10 people. There are six million migraine sufferers in the UK, so those studies are hardly representative." She advises people to be careful when devouring the latest research in the quest for "the Holy Grail of what causes your migraine".

While acknowledging that strokes can be more of a worry to people with migraines, she tells them to keep things in perspective. "There is a very, very, very slightly increased risk of strokes in younger people who suffer from migraines, especially migraines with aura," she says. "But the risk is still minuscule and it's less than if you are a smoker or if you're overweight."

However, she says that women who suffer from migraines and who are on the combined pill are more likely to suffer a stroke than those not on oral contraceptives. "If you suffer from migraine with aura, the combined contraceptive pill is not recommended. And if you take the pill and get migraines for the first time, talk to your doctor."

Sufferers' other big fear is the brain tumour. But this is rarely the cause of migraines. "Brain tumours rarely present as headaches - they normally show themselves as tics or loss of vision," says Dowson.

"With brain tumours, you might have a fit, but not a headache," agrees MacGregor. "A lot of people with migraines come to see us and they are very worried that they might have brain tumours. It may sound a bit crass, but we tell them that if they really did have a brain tumour, it would only be getting bigger and bigger inside their head and that they wouldn't be feeling fine between migraines."

And what of Hughes syndrome, the "sticky blood" condition that makes blood clot too easily? Recent reports suggest that migraines may be one of the symptoms of the syndrome, which is responsible for 20% of strokes in people under the age of 45, as well as cases of deep-vein thrombosis and recurrent miscarriages. "With Hughes syndrome, you will have had other symptoms, such as recurrent miscarriages or bleeding problems," she says.

The experts are keen to stress that migraine should be accepted for what it is: an illness in its own right that is not necessarily connected to the dreadful ailments we read about. Migraine sufferers are born with a genetic disposition that leaves them susceptible to attacks. The head-aches, which generally occur at the rate of one a month, can be brought on by missing meals or being stressed. In women, their severity and duration can be affected by the menstrual cycle.

"The majority of people with migraine do not have it secondary to another cause," says Dr MacGregor. "If somebody has recurrent, sick headaches but is otherwise perfectly well, it is extremely unlikely that there is anything more serious wrong with them. But if there are other problems besides your migraine, that is when you start looking for other causes, like whether you were born with an aneurysm or whether you have heart valve problems."

Dowson agrees: "The thing to remember is that migraine is enough of a high-impact illness on its own without worrying about other conditions. People with migraines often need help so they can do their jobs as usual and live normally. In terms of the impact it has on your life, it's similar to diabetes."

Turner admits treatment for migraines can be a bit of a "pick and mix"affair, but says it is preferable to letting the illness control your life. "It may sound negative, but you have to accept that migraines are a part of who you are. But there are lots of things you can do to get your life back. The best way of doing that is to keep a diary of what you do and what you eat and going to see your doctor."

The best medicine, reckons MacGregor, is often common sense: "The majority of people with migraines shouldn't worry. Remember that the cold you had was a cold, not pneumonia, and the chest infection was just that, and not underlying lung cancer. But if you are worried about underlying causes and symptoms, go and see your doctor."