BBC Health Correspondent James Westhead: Research quashes fears of long-term side-effects

Until now the extent of the effect the pill had on long-term health was unknown.

The study showed that, although women who take the contraceptive pill have a slightly greater risk of certain types of cancer, heart attacks, stroke and thrombosis, the risk disappeared 10 years after pill use ended.

Doctors hailed the finding as good news for women, while family planning advisors said it should lead to improved prescribing practice and better patient information.

However, the study was based mainly on women who started taking the pill in their twenties.

Family values campaigners said there is a body of evidence suggesting a massively increased risk of breast cancer in women who start taking the pill young.

Findings

Worldwide it is estimated that 300 million women have used the pill, with 100 million currently taking it.

The study looked at 46,000 women in the UK who started taking the pill during 1968-69 and followed them for a period of 25 years.

The results of the study, a collaborative venture between the Royal College of General Practitioners (RCGP) and the Imperial Cancer Research Fund (ICRF), will be published in the British Medical Journal.

Professor Valerie Beral is director of the ICRF's cancer epidemiology unit in Oxford.

She said: "This is good news for women. We have known for a long time that there is a small risk associated with taking the pill.

"Our new figures show that by the time women who've used the pill have been off it for 10 years, their risk of developing the conditions is similar to what it would have been if they had never taken the pill at all."

The analysis used figures from the RCGP's Oral Contraception Study, which covers 46,000 women registered with 1,400 GPs around the UK.

The average age of the women was 50 and most of them had used a combined pill containing 50mcg of oestrogen.

Of these women, 1,600 died during the 25-year period studied.

By examining the causes of death, the researchers established that women who had taken the pill were no more likely to die prematurely than women who had not.

Individual factors

Professor Philip Hannaford explains the significance of the findings

Professor Philip Hannaford, who directs the continuing study, said that, while this analysis looked at all causes of death, other research is looking at risk factors for specific conditions.

He said the findings so far pointed to the same trend - that there is no greater long-term risk associated with use of the pill.

Even so, he said, the short-term risks were slight and in most cases specific to the individual.

"We now know that most of that risk is in current users who also have other risk factors, mainly current users who smoke or have hypertension."

Victoria Gillick: Research shows greater risks

However, Victoria Gillick, a pregnancy counsellor who campaigns for family values, said there was evidence that starting the pill before the age of 20 led to a 50% increase in the risk of breast cancer.

She said she had seen young women who had been on the pill since they were 12.

Professor Beral published work last year that showed no increased risk of breast cancer 10 years after stopping taking the pill.

Ms Gillick said it also confirmed "10 or more other pieces of research" that showed "the pill may not be dangerous for older women, but it is certainly a risk for young women".

New users

Dr Gillian Reeves: "The adverse effects decline over time"

Dr Gillian Reeves, one of the report's authors, said the 25-year study added to the body of evidence showing the pill was safe, but that starting it was a question of weighing up risks and benefits.

The present study referred to women who took early high-dosage pills, so the implications for current users were slightly different.

"You can't say directly what would happen to women who are taking new generation pills today," she said.

"But one would hope that because those pills are lower doses then if anything they would be safer."

"Obviously there is still ongoing research that will address that directly."

Toni Belfield outlines the practical implications of the research

Toni Belfield, of the of the Family Planning Association, said the increased level of knowledge about the risks should lead to better practice in starting people on the pill.

"We want to see improved prescribing practice, improved information for women so they feel more confident about taking it," she said.

"The pill is very safe for women who are appropriate to take it - that is, women who don't have any risks in the first place," she added.

Gillian Vanhegan is medical spokeswoman for Brooks Advisory Centres, which provides free advice on contraceptive methods.

She said: "For younger women considering the use of the pill now, it is important to be aware of any family or personal history concerning circulatory disorders.