Multiple sclerosis linked to contraceptive pill: Risk could be up to 50% higher in women who take it

Study examined 305 U.S. women diagnosed with MS and 3,050 without it



Those who had used the Pill were 35 per cent more likely to develop MS



Research presented at American Academy of Neurology in Philadelphia

Taking the contraceptive Pill may increase a woman’s chance of developing multiple sclerosis, researchers warn.

The risk of MS could be up to 50 per cent higher among women on the Pill, according to a new US study.

The findings also show young obese women are at greater risk of the disease, probably because they produce higher levels of a hormone known to regulate appetite.

Warning: A U.S. study of more than 3,300 women found more developed MS if they used the Pill

Previous research had suggested that oral contraception could cut MS risk, or delay its onset.

MS is the most common disabling neurological condition, affecting almost 100,000 Britons – 50 young people are diagnosed each week.

It involves damage to myelin, a protective sheath surrounding nerve fibres of the central nervous system, meaning the body’s immune system attacks itself.

Symptoms range from mild, occasional illness involving numbness, muscle weakness and eye problems to rapid and severe deterioration, resulting in serious disability.

Popular: The contraceptive pill is used by millions

US researchers identified 305 women who had been diagnosed with MS during a three-year period.

Their use of the Pill – mainly a combination of two hormones – was compared with 3,050 women who did not have MS.

In total, 29 per cent of the women with MS and 24 per cent of those without MS had used hormonal contraceptives for at least three months in the three years before symptoms began.

Women who had used the Pill were 35 per cent more likely to develop MS than those who did not use them. Those who had used the contraceptives but had stopped at least one month before symptoms started were 50 per cent more likely to develop MS.

Lead researcher Dr Kerstin Hellwig said: ‘These findings suggest that using hormonal contraceptives may be contributing at least in part to the rise in the rate of MS among women.’

Previously animal research led experts to believe female hormones might delay the onset of MS, and a British study suggested Pill users had a 40 per cent lower risk.

The new research was presented at the American Academy of Neurology’s annual meeting in Philadelphia.

In a separate study at the same meeting, researchers looked at a possible link between obesity and MS, by checking the Body Mass Index (BMI) of study volunteers.

BMI was calculated for 210 people with MS and 210 people of the same age and sex who did not have MS at ages 15 and 20 and at the time of the study.

The study found that people who are obese at age 20 are twice as likely to later develop MS as people who are not obese.

The study found that people with higher BMI levels also had higher levels of leptin, a hormone made by fat tissue that regulates weight, appetite and immune response.

Study author Dr Jorge Correale, of the Raúl Carrera Institute for Neurological Research in Buenos Aires, Argentina, said: ‘Leptin promotes inflammatory responses in the body, which could potentially explain the link between obesity and MS.’

Dr Hellwig said MS was a relatively rare disease, but most likely to strike women between the ages of 20 and 40 – when they would be taking the pill.

She said: ‘We don’t say it causes MS, but adjusting for other factors more women use the pill who develop MS.'