Taking the Pill has prevented 200,000 cases of cancer over the past decade, a report published on Wednesday revealed.
The study, conducted by the Collaborative Group on Epidemiological Studies on Endometrial Cancer, found women who took an oral contraceptive - even just for a few years - were given substantial long-term protection against endometrial (womb) cancer.
According to the report, published in The Lancet Oncology Journal, the longer the pill was used, the greater that protection became.
The researchers estimated that in the past 50 years (1965-2014) about 40,0000 cases of endometrial cancer have been prevented by oral contraceptive use in high-income countries, including about 20,0000 in the last decade (2005-2014).
Although endometrial cancer is very rare in young women, the risk increases with age - but even when older, women were found to be far less at risk if they had taken the pill.
Study author Professor Valerie Beral, from the University of Oxford, explained: “The strong protective effect of oral contraceptives against endometrial cancer – which persists for decades after stopping the Pill – means that women who use it when they are in their 20s or even younger continue to benefit into their 50s and older, when cancer becomes more common.
“Previous research has shown that the pill also protects against ovarian cancer. People used to worry that the Pill might cause cancer, but in the long term the pill reduces the risk of getting cancer.”
The study pooled data on 27276 women with endometrial cancer in 36 studies from North America, Europe, Asia, Australia, and South Africa—virtually all the epidemiological evidence ever collected on the effect of oral contraceptives.
Interestingly, alcohol use, smoking, ethnicity, reproductive history and amount of body fat seemed to have little effect on the results.
Fiona Osgun, health information officer at Cancer Research UK, said: “We already know that taking the Pill is linked with a long-term reduction in womb cancer risk. And this large study, which Cancer Research UK helped fund, adds more data on how long this effect lasts – showing that women’s risk of womb cancer is reduced for over 30 years after they’ve stopped taking the Pill.
“The Pill can also affect a woman’s risk of other cancer types – increasing her risk of breast and cervical cancers, but also reducing her chances of developing ovarian cancer.”
She added that while it was already known that the Pill could provide protection from cancer of the womb, it had not been realised that this lasted so long.
She said: “What’s really interesting about this study is the part of it that we didn’t have a picture of from other research, that the reduction in risk [of endometrial cancer] lasts for so long.
“We knew that for about 20 years plus there was a reduction in risk but this study is showing that for women who have taken the Pill, that more than 30 years since they stopped taking it are still seeing lower risk than woman who have never taken it. That’s a really interesting part of this.”
According to the BBC, it is estimated that around 70% of women in Britain have used the Pill at some stage in their lives.
Experiences with oral contraceptives tend to vary, with some women complaining of mood changes, spots and weight gain, while others have praised it for regulating periods, clearing skin and ultimately giving them control over their reproductive systems.