A number of things may help reduce your risk of developing breast cancer.
Diet and lifestyle
Exercising regularly and eating a healthy, balanced diet are known to help prevent many forms of cancer, as well as other serious health conditions, such as heart disease and diabetes.
Studies have looked at the link between breast cancer and diet and, although there are no definite conclusions at the moment, there are benefits for women who maintain a healthy weight, take regular exercise and who have a low intake of saturated fat and alcohol.
It's been suggested that exercising regularly (a minimum of 150 minutes or 2 hours 30 minutes a week) can reduce your risk of developing breast cancer by up to a third.
Read more about the physical activity guidelines for adults.
If you've experienced the menopause (when your monthly periods stop), it's very important you're not overweight or obese. This is because these conditions cause more oestrogen to be produced, which can increase the risk of breast cancer.
Read more about preventing breast cancer.
Studies have shown that women who breastfeed are statistically less likely to develop breast cancer than those who don't.
The reasons for this aren't fully understood, but it could be because women don't ovulate as regularly while they're breastfeeding and their oestrogen levels remain stable.
In June 2013, the National Institute for Health and Care Excellence (NICE) announced that two medications, called tamoxifen and raloxifene, would be available on the NHS for women with an increased risk of developing breast cancer.
These medications may not be suitable if you've had blood clots or womb cancer in the past, or if you have an increased risk of developing these problems in the future. If you've already had a mastectomy to remove both breasts you won't be offered these medications because your risk of developing breast cancer is very small.
Either tamoxifen or raloxifene can be used in women who've had the menopause.
A course of treatment with tamoxifen or raloxifene will usually involve taking a tablet every day for five years.
Raloxifene can cause side effects including flu-like symptoms, hot flushes and leg cramps. Side effects of tamoxifen can include hot flushes and sweats, changes to your periods and nausea and vomiting.
Tamoxifen can increase your risk of developing blood clots, so you should stop taking it six weeks before any planned surgery.
Tamoxifen and raloxifene aren't currently licensed for reducing the chances of getting breast cancer in women with an increased risk of developing it. However, they can still be used if you understand the benefits and risks and your doctor believes the treatment will be helpful.
For more information, read Drugs to be offered to women at high risk of breast cancer.
Breast screening can pick up breast cancer before it forms a lump. The procedure uses mammograms, where X-rays are taken, to create an image of the inside of your breasts.
The NHS Breast Screening Programme provides free breast screening every three years for all women in the UK who are 50 years of age or over. In some areas, women aged 47-49 and 71-73 are also invited for screening as part of a trial looking at whether the screening age range should be extended.
NHS breast screening isn't usually available for women under 47 years of age. This is because younger women tend to have denser breast tissue, which makes mammograms less effective at identifying abnormalities.
Speak to your GP if you're below screening age and worried about changes in your breasts, or you have a family history of breast cancer.
Read more about breast cancer screening.