How Breastfeeding Reduces The Risks of Breast Cancer - For You And Your Daughter.

You have most likely heard very good reasons to breastfeed: boosting baby’s immune system; providing breast milk that changes to meet your baby’s needs; a lovely way to bond and allowing instant comfort for an unsettled baby.

Another important reason to consider breastfeeding is evidence that it can reduce your own and – if you have a baby daughter – her risk of breast cancer too.

However, a survey published in the journal, Breastfeeding Medicine, shows that you may not have heard this information from a health professional: although nearly 60 percent of breastfeeding mothers in this study knew about the link between breastfeeding and breast cancer risk reduction, just 16 percent say they learned this from a medical professional.

"This is concerning," says study principal investigator Bhuvana Ramaswamy, MD, breast medical oncology division director at The Ohio State University Comprehensive Cancer Center - Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC - James).

Dr Ramaswamy says, “women should be informed that breastfeeding can reduce breast cancer risk and improve mother's health. Epidemiological studies show strong correlation between prolonged breastfeeding and reduced risk of developing triple negative breast cancer, an aggressive form of breast cancer. We have a duty as a medical community to ensure our patients have reliable knowledge. When it comes from a professional, medical information is much more likely to affect people's choices. When it comes to breast cancer specifically, prevention is the best outcome."

Reducing the risks

Breastfeeding doesn’t mean you won’t get breast cancer or that, conversely, if you don’t breastfeed you will, but there are several compelling studies that demonstrate breastfeeding does reduce the risks:

• Breastfeeding your baby daughter could reduce her chances of getting breast cancer by between 26 and 31 % – so you could be reducing the risks for two people! (1)

• Breastfeeding for 12 months or longer could reduce your chances of breast cancer at any age (pre or post-menopausal) by up to 28% for women without a family history of breast cancer (2)

• For women with a family history of breast cancer, breastfeeding is associated with a nearly 60% reduced risk of developing premenopausal breast cancer. (3)

• The longer a mother breastfeeds - for example, more than 12 months (and this can be over several babies) provides more protection. (4)

• Any breastfeeding – even if you are feeding with some breast milk and some formula – reduces breast cancer risks.(4)

Please check your breasts

However, despite the evidence, if you are breastfeeding, it’s still important to regularly check your breasts.

As a new mum engulfed in adjustment, exhaustion and the constant needs of a newborn, it can be easy to put your own health low on the priority list. And, of course, lumps and bumps and breast changes are a natural part of the breastfeeding experience, so can easily be dismissed.

As a lactation consultant, I have supported mothers through the trauma of weaning due to breast cancer diagnoses and I want to stress, please don’t accept that lumps that don't go away or breast changes are due to mastitis or an inevitable side effect of breastfeeding, even if you are told this by a health professional.

Although lumps while breastfeeding are usually due to blocked ducts, these should clear in a few days, not linger on. If a lump doesn’t go away or you notice any changes to your breasts or nipples or if something simply doesn’t feel right, it’s important to insist on further investigation such as an ultrasound.

At best, you will be relieved that you are healthy, at worst, an early diagnosis could be life-saving. Trust your instincts – if something doesn’t feel right, get it checked.

What if you don’t breastfeed?

Whether you are breastfeeding or not, there are other important risk reduction practices. According to a 2008 report published by the National Institutes of Health (USA), 90 – 95% of cancer cases have their roots in environment and lifestyle, so a healthy diet, exercise, reducing alcohol intake and avoiding smoking can all make a significant difference.


 1) Freudenheim J.L., et al. Exposure to breastmilk in infancy and the risk of breast cancer. Epidemiology. 1994 May; 5(3): 324-31.


3) Lactation and Incidence of Premenopausal Breast CancerA Longitudinal Study Alison M. Stuebe, MD, MSc; Walter C. Willett, MD, DrPH; Fei Xue, MD, ScD; et alKarin B. Michels, ScD, PhD Arch Intern Med. 2009;169(15):1364-1371. doi:10.1001/archinternmed.2009.231

4) Collaborative Group on Hormonal Factors in Breast Cancer Familial breast cancer: collaborative reanalysis of individual data from 52 epidemiological studies including 58 209 women with breast cancer and 101 986 women without the disease. Lancet. 2001; 358: 1389-1399