Read about the factors that can increase or reduce your risk of ovarian cancer.
We don’t know what causes most ovarian cancers. But there are some factors that may increase your risk of developing it.
Possible risk factors for ovarian cancer
The following factors may increase the risk of ovarian cancer:
As with most cancers, the risk of developing ovarian cancer increases as you get older. Most cases of ovarian cancer happen in women who have had their menopause.
Inherited faulty genes
Most ovarian cancers are due to gene changes that develop during a woman’s life and are not inherited. But between 5 and 15 out of 100 ovarian cancers (5 to 15%) are caused by an inherited faulty gene. Faulty inherited genes that increase the risk of ovarian cancer include BRCA1 and BRCA2. These genes also increase the risk of breast cancer.
If you are worried about your family history of ovarian cancer, speak to your GP. They can tell you whether you need a referral to a genetics service.
Previous breast cancer
Breast cancer and ovarian cancer can sometimes be due to the same faulty genes. Women who have had breast cancer have up to double the risk of developing ovarian cancer compared to other women in the population, and if their breast cancer was diagnosed before the age of 40, their risk is even higher.
If you think you may have a faulty gene, speak to your GP.
Being infertile or having fertility treatment
Some older studies showed a link between taking fertility drugs and an increased risk of ovarian cancer. But more recent research doesn't support this.
It is more likely that infertility itself increases ovarian cancer risk, rather than fertility treatment being the cause. More research is happening to clarify this.
Using hormone replacement therapy (HRT)
In the UK, less than 1 in 100 (1%) of ovarian cancers are linked to hormone replacement therapy (HRT) use.
Being overweight or tall
Researchers looked at the risk of being overweight in premenopausal and postmenopausal women. They found that the risk of ovarian cancer was higher in premenopausal women with a BMI above 28, but there was no effect in postmenopausal women.
Ovarian cancer risk is higher in women who have a high BMI and have never used HRT. Women who have a high BMI and have used HRT have a lower risk of developing ovarian cancer.
Research has also found that taller women have a higher risk of ovarian cancer than shorter women.
Research has shown that women with endometriosis have an increase in their ovarian cancer risk compared to women who do not.
Using talcum powder
Using talcum powder between your legs is thought to increase the risk of ovarian cancer. The powder could, in theory, travel up into the vagina and then through the cervix into the womb. If it then worked its way down the fallopian tubes to the ovaries, it could get into the ovaries themselves and cause irritation. Constant irritation could potentially cause inflammation and lead to cancerous changes in cells.
Smoking can increase the risk of certain types of ovarian cancer such as mucinous ovarian cancer. The longer you have smoked, the greater the risk.
For other types of ovarian tumours, such as clear cell and ovarian endometrioid cancer, how much smoking affects risk varies.
There has been a lot of research into the effect of dietary factors on ovarian cancer risk and so far most findings have been inconclusive and inconsistent. This may be because there is either no link between diet and ovarian cancer, or it is very small. Or it might be because of problems with the design of the studies.
Some studies have shown that a diet high in fats, particularly animal fats, may increase your risk of ovarian cancer. But more research is needed before we know whether changing our diet can reduce the risk of ovarian cancer.
Possible protective factors
The following factors may reduce your risk of ovarian cancer:
Taking the contraceptive pill
Taking the contraceptive pill at some point in your life reduces your risk of cancer of the ovary. Research has shown that the longer you take the pill, the more your risk is thought to come down. The reduction in risk lasts for at least 30 years after you stop taking the pill.
Having children seems to reduce the risk of ovarian cancer. The more children a woman has, the lower the risk.
Breastfeeding might lower the risk of ovarian cancer. This may be because your ovaries normally stop producing eggs each month while you are breastfeeding.
A study has shown that women who breastfed have a lower risk of getting ovarian cancer compared with women who never breastfed. The risk was lower in women who breastfed for a longer time.
Having a hysterectomy or having your tubes tied
Having your tubes tied because you don't want any more pregnancies is called sterilisation. Two recent meta-analysis studies combined the results from all of the research looking at this. These studies both found that having your tubes tied reduces the risk of ovarian cancer.
Until recently, most research has shown that having your womb removed (hysterectomy) may also reduce your risk of ovarian cancer. But newer evidence suggests that there is a higher risk of ovarian cancer for women who have had a hysterectomy in recent years. Researchers think this might be because these days it is less common for younger women to have a hysterectomy. It may also be something to do with a change in the number of women having their ovaries removed, and the use of HRT after hysterectomy.
Non-starchy vegetables (such as broccoli, cabbage and onions) may decrease ovarian cancer risk but the evidence is uncertain.
Other possible causes
Stories about potential causes are often in the media and it isn’t always clear which ideas are supported by evidence. There might be things you have heard of that we haven’t included here. This is because either there is no evidence about them or it is less clear.