The contraceptive Pill can protect women against cancer in later life, media reports have claimed.
UK researchers found that taking the Pill could cut a woman's risk of cancer of any kind by up to 12 per cent. This amounts to one fewer case of cancer for every 2,200 women using the Pill. But those who used the Pill for more than eight years - a quarter of those in the study - had a slightly increased risk of cervical cancer.
While there have been hundreds of studies into the safety of the Pill since it was launched in 1961, this is the first study to pull all the cancer implications together, say the papers.
What is the research?
The reports are based on one of the largest studies into the safety of the Pill.
The researchers analysed data spanning a 36-year period obtained from the RCGP Oral Contraception Study, which began in 1968.
Over 14 months, 1,400 GPs recruited 46,000 women, with an average age of 29.
Approximately half of the women were using oral contraceptives, while the other half had never taken oral contraceptives.
Every six months, their GP provided the study with information on the women's general health.
Additionally, three quarters of the women were flagged at NHS central registries. This meant that deaths and cancers were highlighted even if women moved to a different GP practice.
The data was then used by the researchers to calculate the risk of developing any type of cancer and the main gynaecological cancers combined.
Due to the length of the study, a significant number of GPs were unable to provide updates throughout the entire study period, so the researchers decided to calculate cancer risks using two sets of data.
One related to cancers reported while the women remained registered with their original GP. A second, larger dataset included cancers notified by the central NHS registries after women had left their original GP.
The risk of developing any cancer was lowered by 3 per cent in the original GP dataset with Pill use. In the second dataset, which included NHS registries, the risk decreased by 12 per cent.
What do the researchers say?
Lead researcher Professor Philip Hannaford, from the department of general practice and primary care at the University of Aberdeen, said the study's findings were reassuring for women.
'In this UK cohort, oral contraception was not associated with an overall increased risk of any cancer. It may even produce a net public health gain.'
There was a 22 per cent increase in cervical cancer risk for women who had been using the Pill for more than eight years, said Professor Hannaford.
'However, this reflects a worst-case scenario as the study began before the cervical cancer screening programme was introduced. GPs should advise women that if they do use the Pill for a long period, they should make sure they have a regular smear test.'
What do the experts say?
Dr Julie Sharp, Cancer Research UK's science information manager, said: 'For many years we have known that oral contraceptives temporarily increase the risk of some cancers, while reducing the risks of others.
'This study looks at the long-term effects of taking the Pill and it suggests that users are at no greater risk of cancer over their lifetime than non-users.
'It remains important for women to be aware of the short-term risks of using the Pill, such as an increased risk of breast and cervical cancer.'
But this research suggests that these risks may be balanced out by health benefits over the longer term, she added.
- Taking the Pill can lower the risk of cancer in later life by 12 per cent.
- But a slight increase in cervical cancer risk was found in women who took the Pill for longer than eight years.
- GPs should advise women who use the Pill for long periods of time to go for regular smear tests.