The benefits of the contraceptive pill far outweigh the risks

A study by researchers in Scotland confirms that for most women who take the contraceptive pill, the benefits far outweigh any potential risks.

Since they were first introduced in the early 1960s more than 300 million women have used oral contraceptives.

This latest study by researchers at Aberdeen University has analysed data over almost four decades and is one of the largest and longest follow-up studies to examine the issue.

The study included 46,000 women followed for 36 years from the late 1960s through to 2004, when most were in their early to late 60s.

The study began in 1968, and updates on the women's health were provided every six months by their doctors which continued even if the women moved to a new doctor.

The average age of the women in the study was 29 at recruitment between 1968 and 1969 and about half used oral contraceptives while the other half did not.

The researchers were able to obtain details of whether they developed cancer, or died from National Health Service (NHS) central registries.

The researchers found that the risk of cancer was up to 12% lower among those women who had taken the pill and the risk of large bowel, uterine and ovarian cancer was statistically significant.

The researchers say that equates to one fewer case of cancer for every 2,200 women who took the pill for a year.

There have been a number of studies over the years which have examined the impact of oral contraceptives on cancer risk and the consensus is that the contraceptive pill slightly increases the risk of breast, cervical and liver cancer while they are on the pill and for a few years after.

The evidence from this study suggests that the protective effect of taking the pill lasts for at least 15 years after the pill is stopped and often carries over into the period when women become more susceptible to developing cancers.

However, women who used the pill for more than eight years - less than a quarter of pill users who took part in the study - had a statistically significant increased risk of developing cancer, particularly cervical and central nervous system cancer but the same women were at reduced risk of developing ovarian cancer.

Lead researcher Professor Philip Hannaford says the findings should reassure many women, especially those who used first generation oral contraceptives.

Dr. Hannaford says comprehensive cervical cancer screening, which is the norm today but was not in the early years of the study, can minimize this risk for long-term oral contraceptive users.

The researchers say however that the different modern pill formulations, and the fact that many women now take the pill at a younger age, and stay on it for longer, may modify the risk of cancer.

But they also believe from the available evidence that currently used contraceptive pills produce broadly similar effects.

Professor Hannaford says it is unusual for women to take the pill for as long as eight years, as they tend to use the pill on and off depending on their personal circumstances.

He says though he does not recommend women take the pill specifically to reduce their risk of cancer, if they do decide to take it they are not putting themselves at risk by doing so.

Many experts agree and say the benefits outweigh the risks and say any increased risk of breast and cervix cancer linked to pill use appears to be cancelled out by long-term protection from other cancers.