Factors such as physical activity, breastfeeding, alcohol and others can affect our risk of developing breast cancer.

Our lifestyle choices and the way we lead our day-to-day lives can affect our risk of developing breast cancer. For more information on any of the below factors, download our pdf booklet Breast cancer risk: the facts.

The following factors can reduce the risk of breast cancer developing:

Physical activity

Regular physical activity will help to reduce your risk of breast cancer, particularly after the menopause. Physical activity includes structured exercise and other moderate physical activity, such as walking, housework, cycling at a casual pace, actively playing with children and gardening. If you want to reduce your risk of breast cancer, we recommend you are regularly physically active. Find out more about physical activity and reducing your breast cancer risk.

Download our factsheet: Physical activity and breast cancer risk.

Breastfeeding

Breastfeeding your children slightly reduces your risk of breast cancer. The longer you breastfeed in total, the more your risk of breast cancer is reduced. For example, breastfeeding one child for one year would lower your risk of breast cancer as much as breastfeeding two children for six months each.

Breastfeeding may reduce breast cancer risk by altering the balance of hormones in the body and by delaying the return of a woman’s periods. There are many important benefits associated with breastfeeding for both mother and child, but the decision to breastfeed needs to be a personal one. While many women breastfeed, not all women choose to and others find it difficult or are unable to for a number of reasons.

National health guidelines recommend that women breastfeed exclusively for the first six months of an infant’s life as it provides all the nutrients a baby needs. After that, giving your baby breast milk alongside other food will help them continue to grow and develop healthily.

If you are breastfeeding, you should examine your breasts for any unusual changes. It is common for breasts to be lumpy during breastfeeding, but if you notice anything unusual or have any concerns, talk to your doctor. 

Read our blog, 'Does breastfeeding affect your risk of breast cancer?'

The following factors increase the risk of breast cancer developing:

Alcohol

Regularly drinking alcohol increases your risk of developing breast cancer. The more drinks that you have each day, the greater your risk of breast cancer will be. If you want to reduce your risk of breast cancer, we recommend you limit the amount of alcohol you regularly drink throughout your life. Learn more about alcohol and breast cancer risk.

Download our factsheet: Alcohol and breast cancer risk.

Hormone replacement therapy (HRT)

Using HRT to treat menopausal symptoms can slightly increase  your risk of breast cancer during the years you take it. The longer you use HRT, the greater your risk. But once you stop taking HRT, this risk will begin to fall. Within a year or two, it will be about the same as if you had never taken it. Find out more about HRT and breast cancer risk

The pill

Taking the combined contraceptive pill (which contains oestrogen and progestogen) can slightly  increase your risk of breast cancer. Your risk will drop back to normal within a few years of stopping.

It’s important to mention that breast cancer is rare in young women. Most women using the combined pill are in their late teens, twenties and early thirties. So a slight increase in breast cancer risk during this time means only a small number of extra cases of breast cancer are diagnosed. Find out more about the pill and breast cancer risk

Pregnancy

Having children has a complex effect on breast cancer risk. Overall, in the long term, pregnancy reduces the risk of breast cancer.

Having children affects breast cancer risk in different ways:

  • Women who have had children are at lower risk of breast cancer in the long term than women who have not had children. The more children you have, the greater the decrease in risk.
  • The age at which you have children affects your risk of developing breast cancer. The earlier a woman begins her family, the lower her risk of breast cancer.
  • In the short term, research studies suggest that your risk of breast cancer slightly increases after you give birth, regardless of your age. We don’t know the reasons for this, but it may be caused by hormone changes. This increase in risk is temporary, lasting a number of years, and it is important to remember that breast cancer is rare in women under 50. 

Weight

There are three known links between weight and breast cancer:

  • Putting on weight in adulthood (after the age of 18) increases your risk of developing breast cancer after the menopause.
  • Being overweight or obese before the menopause slightly reduces your risk of developing breast cancer before the menopause.
  • Being overweight or obese after the menopause increases your risk of breast cancer.

Find out more information about weight and breast cancer risk.

Download our factsheet: Weight and breast cancer risk.

For the following factors, there is some scientific evidence that suggests they may affect the chances of developing breast cancer

More research is needed before we can be sure whether or not they are definitely linked to the disease.

Healthy diet

Maintaining a healthy diet might help to reduce your risk of breast cancer, as well as other cancers. However, we still aren’t sure whether any specific dietary factors influence the chance of developing the disease.

It is unlikely that phyto-oestrogens (found in soya and some other foods) increase your risk of developing breast cancer.

For more information on how to maintain a healthy, balanced diet, you may wish to speak to your doctor or visit the NHS Choices website

Aspirin and ibuprofen

Taking aspirin or ibuprofen might slightly reduce the risk of breast cancer, but we don’t recommend that women take these drugs solely to lower their risk of breast cancer.

Aspirin and ibuprofen are types of non-steroidal antiinflammatory drugs (NSAIDs). Taking these drugs might slightly reduce the risk of breast cancer, but not all studies agree. In addition, we do not know how different doses of these drugs affect breast cancer risk or for how long they would need to be taken to have an effect.

NSAIDs, including aspirin and ibuprofen, can have serious side effects when taken over a long period, including stomach ulcers, anaemia and, less commonly, heart problems. It is important that women who want to take these drugs regularly for any reason consult their doctor first.

Because we don’t know enough about how these drugs affect breast cancer risk, Breast Cancer Now does not recommend that women regularly take them in order to lower their risk of breast cancer. 

In vitro fertilisation treatment (IVF)

It is unclear whether IVF treatment affects the risk of breast cancer because only a very small number of studies have looked into this. IVF treatment increases the levels of female hormones such as oestrogen in the body, which is why some people speculate it may increase the risk of breast cancer.

One study suggests that, overall, women who have received IVF treatment are no more likely to develop breast cancer than women who have not had IVF. Although women undergoing IVF may have a slightly higher risk of breast cancer in the first year after treatment, this risk disappears in the following years.

It may be that having IVF over the age of 30 or 40 slightly increases your risk of breast cancer, but until more research is available we will not know whether or not this is the case. IVF is a relatively new procedure and we don’t know its long-term health effects.

If you are worried about IVF treatment and breast cancer risk you should discuss your concerns with your doctor or fertility specialist.

Smoking

Smoking may increase your risk of developing breast cancer but there is not enough evidence for us to be sure. Recently, some studies have shown that smoking increases the risk of breast cancer; however, some older studies did not find a link.

Regardless of any potential breast cancer risk, smoking is a major cause of lung cancer and other cancers, as well as heart disease – all women and men are strongly advised not to smoke by health professionals, the government and health charities.

For information and advice on stopping smoking, contact your doctor or visit the NHS Choices website

Need more information?

Breast Cancer Now has developed several free fact sheets that look in more detail at the effect of some factors on breast cancer risk. For an up-to-date list of the fact sheets available to download or order printed copies visit our breast cancer resources.

What should I do if I am worried about the risk factors mentioned here?

If you are worried about any of the breast cancer risk factors mentioned here you should discuss your concerns with your doctor.

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Information last reviewed: November 2017

Next review due: November 2020

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