The Who, What, Where, When and Sometimes, Why.


Breastfeeding and breast cancer risk

Women who breastfeed have a lower risk of breast cancer, especially before menopause, than women who don’t breastfeed [10,17,121-124].

A pooled analysis of data from 47 studies found that compared to mothers who never breastfed, [122]:

  • Mothers who breastfed for a lifetime total (combined duration of breastfeeding for all children) of one year were slightly less likely to get breast cancer.
  • Mothers who breastfed for a lifetime total of 2 years got about twice the benefit of those who breastfed for a total of one year.
  • Mothers who breastfed for a lifetime total of more than 2 years got the most benefit.

Although data are limited, breastfeeding for less than one year may also be linked to a lower risk of breast cancer [122].

Triple negative breast cancer

Breastfeeding may be more be more strongly linked to a lower risk of estrogen receptor-negative (including triple negative) breast cancers than estrogen receptor-positive cancers [12,123-128].

For a summary of research studies on breastfeeding and breast cancer, visit the Breast Cancer Research Studies section.

Learn about other healthy lifestyle behaviors that may lower breast cancer risk.

Other health benefits of breastfeeding

Breastfeeding has other benefits for mothers. Compared to those who don’t breastfeed, women who breastfeed have a lower risk of [129-131]:

  • Type 2 diabetes
  • Ovarian cancer




1. Know your risk

2. Get screened

3. Know what is normal for you and see a health care provider if you notice any of these breast changes (see images):

  • Lump, hard knot or thickening inside the breast or underarm area
  • Swelling, warmth, redness or darkening of the breast
  • Change in the size or shape of the breast
  • Dimpling or puckering of the skin
  • Itchy, scaly sore or rash on the nipple
  • Pulling in of the nipple or other parts of the breast
  • Nipple discharge that starts suddenly
  • New pain in one spot that doesn’t go away

4. Make healthy lifestyle choices

Download our Breast Self-Awareness Messages resource for more information.

Updated 03/08/22