Breastfeeding and Breast Cancer Risk

August is national breastfeeding month, learn how breastfeeding can affect breast cancer risk.

Breastfeeding lowers the risk of breast cancer, especially in premenopausal women.

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

Mothers who breastfed for a lifetime total (combined duration of breastfeeding for all children) of 1 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 1 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 1 year may also modestly lower breast cancer risk.

Triple negative breast cancer

Breastfeeding may be especially good at lowering the risk of estrogen receptor-negative (including triple negative) breast cancers.

Other health benefits of breastfeeding

Breastfeeding has other benefits for mothers, including lowering the risk of:

Type 2 diabetes

Ovarian cancer

Postpartum depression


More Information About the Studies