The contraceptive Pill
High levels of our own natural hormones can increase our risk of some cancers, such as breast and womb cancers. Some medical treatments, including hormone replacement therapy (HRT) and the birth control Pill, work by increasing levels of certain hormones. So scientists have investigated whether using them could affect the risk of developing cancer.
This page will talk about the Pill and whether it affects your cancer risk.
Different types of Pill
Oral contraceptives, commonly known as ‘the Pill’, are a popular form of birth control in the UK. There are two main types:
- The combined Pill. This is by far the most common type and consists of two female hormones - oestrogen and progestogen.
- The mini-Pill. This pill only contains progestogen, it's also known as the progestogen-only Pill or POP.
The combined Pill and cancer
Scientists have found that the combined Pill:
- Reduces the risk of ovarian and womb cancers.
- Increases the risk of cervical and breast cancers.
The longer a woman takes the combined Pill for, the higher her risk of cervical cancer becomes during that time. Taking it for only a short time may not have any noticeable effect, but women who have been using it for 5 years or more have nearly double the risk of developing cervical cancer compared to women who have never used the combined Pill. However, the risk starts to fall back down again once a woman stops using it, so that from about 10 years after stopping her risk is no longer affected.
Scientists used to believe that the Pill only indirectly raised the risk of cervical cancer. The idea was that women who used the Pill were more sexually active and more likely to get infections with HPV - a sexually transmitted virus that can cause cervical cancer. But more recent research, which has tried to take account of women's sexual behaviour, and also whether they're likely to have taken up cervical screening, has still found an increase in risk which scientists believe is down to the combined Pill itself.
The combined Pill also slightly increases a woman's risk of breast cancer. But this risk increase disappears within 10 years of stopping the Pill.
But the combined Pill also offers some protection against certain cancers. It reduces a woman's risk of ovarian and womb cancers. These protective effects are bigger the longer she takes the combined Pill for and continue for decades after she stops taking it.
Taking the combined Pill can also increase the risk of developing liver cancer, in women who take it for a long time and are free of liver disease and hepatitis infections. And there is evidence it can reduce the risk of bowel cancer.
The mini-Pill and cancer
Because fewer women use the mini-Pill, it's harder for scientists to investigate enough women to be sure any effect they see isn't down to chance. Based on a small number of studies, it looks as if the mini-Pill affects a woman's risk of cancer in the same way as the combined Pill. It could slightly increase the risk of breast and cervical cancers, but protect against womb and ovarian cancers. But we can't say this for sure until larger studies are done.
Should I use the Pill?
Your doctor can help you to make an informed choice about whether to use the Pill. This decision should weigh up the risks and benefits, your lifestyle, your personal preferences, and whether you have a strong family history of cancer.
The protective effects of the Pill against womb and ovarian cancers last longer than the increased risks of breast and cervical cancers. Overall, this means that the protective effects outweigh the increased risk of cancer if you look at all women who have taken the Pill. But even though on average the level of protection is bigger than the extra risk, so the chances are you'll benefit, some individual women will develop cervical or breast cancer because they have used the Pill.
Bear in mind that while the Pill can increase the risk of breast and cervical cancers, there are national screening programmes for both these cancers. Breast screening can help detect the disease at an early stage when treatment is more likely to be successful. Attending cervical screening can help get changes in your cervix detected before they develop into full-blown cancers. And younger women will have been offered HPV vaccination, which reduces the risk of developing cervical cancer by helping prevent infection by HPV - the virus that is needed for this type of cancer to start.