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Last Updated: Tuesday, 28 March 2006, 07:35 GMT 08:35 UK
Birth pill 'may cut cancer risk'
contraceptive pills
The combined pill has been linked to breast cancer
Experts are developing a contraceptive pill they hope will not carry the raised risk of breast cancer associated with the current combined pill.

It is hoped the new pill, which may actually protect against the disease, could be available within five years.

Professor David Baird, of the University of Edinburgh, said it might also treat fibroids, endometriosis, and pre-menstrual syndrome.

However, experts have warned the work is at a very early stage.

There is no theoretical reason why the new pill should increase the risk of breast cancer, as it does not contain oestrogen - if anything it might be expected to reduce the risk
Professor David Baird

The pill is based on the drug used in the controversial abortion pill - RU486.

It would stop the monthly cycle of periods by blocking the hormone progesterone, which helps the body prepare for pregnancy.

It might also cut the risk of thrombosis for older women who are overweight or smoke.

Reduced risk

The current combined pill, which contains progesterone and another female sex hormone oestrogen, has been linked to an increased risk of breast cancer.

Much of this effect is thought to be due to the oestrogen component.

However, this link is still disputed, and the combined pill is thought to protect against other cancers, such as womb and ovary cancer.

Professor Baird said animal tests showed the new pill actually inhibited the development of breast cancer.

And he said it was theoretically possible that the drug would have the same impact on human cells.

He said: "There is no theoretical reason why the new pill should increase the risk of breast cancer, as it does not contain oestrogen - if anything it might be expected to reduce the risk.

"If you reduce the cyclical exposure of the ovary to the ovarian hormones oestrogen and progesterone, you should reduce the risk of breast cancer."

The pill has been tried on two groups of around 90 women with positive results and "very few" side effects.

But Professor Baird said larger studies were needed to fully assess the benefits, and potential side effects.

The drug on which the pill is based - mifepristone - was first created in 1980, and has subsequently been used in high doses in the abortion pill.

Professor Baird said there had been difficulty in funding research because of this link, although the new pill uses the drug in far smaller doses.

Early stage

Anna Glasier, of the London School of Hygiene and Tropical Medicine, said the idea that it was unnatural to stop periods was "completely wrong".

She said in years past women would often go years without having periods as they were constantly either pregnant or breastfeeding.

Dr Rosemary Leonard, a London GP and medical writer and broadcaster, warned that the research was still at a very early stage.

"This is highly speculative. It is really not yet known how this particular pill works, and what the long-term implications are.

"Once you start talking about stopping the action of the ovaries, you then start looking at the whole hormonal picture, and that is when you think: what is this doing to long-term health?"

Dr Lesley Walker, of the charity Cancer Research UK, said the drug had only been tested in small groups of women for a short period of time.

She said the research seemed promising, but was concerned about the possible long-term effect on the odds of developing womb cancer.

According to the Family Planning Association (FPA), about 3.4 million women in the UK take either the mini or combined pill, with two million of those taking the combined pill.

A FPA spokeswoman said: "We welcome all new research that looks to provide safe and effective contraception for women."

How the contraceptive pill has changed


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