How Breastfeeding May Lower Your Risk of Breast Cancer

Woman cuddling close and bonding with her baby

Most often breastfeeding conversations and education focus on how great it is for babies, and it is! In fact, human milk is the most complete nutrition available for infants and there are many additional positive impacts that go beyond nutrition and into bonding, emotional regulation, mouth and facial formation, and even neurological development. Breastfeeding really is pretty great for babies.

But did you know that breastfeeding is good for the one producing the milk, too?

There are so many health benefits that come from lactating and while we focus first on what a baby gets from being breastfed, the benefits for the breastfeeding mother are compelling as well. If you lactate, you lower your risk of heart conditions, type 2 diabetes, high blood pressure, and some types of cancers.

Including breast cancer.

Breastfeeding and Breast Cancer Risk

Mother holding up baby who playfully suckles on mother's noseMother holding up baby who playfully suckles on mother's nose

If you are able to lactate and exclusively feed your baby your milk for six months as is recommended by every major health organization in the world, you already lower your risk of breast cancer. Continuing to nurse after introducing solids to at least the recommended 2 years of age (you can always go longer if you’d like!) is one of the top known means to lowering breast cancer risk.

In fact, research shows that for every 12 months of lactating, breast cancer risk decreases by 4.3%. If you have two children and nurse them both to at least the minimum recommendation, you could reduce your breast cancer risk by 17.2% and that number just goes up the longer you breastfeed.

Related, studies have found that breastfeeding for longer than 31 months can reduce ovarian cancer risk by 91%. See? Breastfeeding is very much not just good for the baby!

Breastfeeding and Breast Cancer Prevention: How it Works 

Mother cuddling next to and watching her sleeping babyMother cuddling next to and watching her sleeping baby

Understanding how breastfeeding lowers breast cancer is an ongoing area of study. Researchers don’t fully know why breastfeeding lowers breast cancer risk or how, but many believe that the pause in menstruation, called lactation amenorrhea, caused by the hormone changes experienced in lactation may play a role.

This is due to lowering the breastfeeding person’s lifetime exposure to high estrogen levels. Since estrogen can promote breast cancer cell growth, having periods of time with lower levels may reduce that possibility.

However, lowered estrogen levels is one possible reason breastfeeding may reduce one’s chances of breast cancer. Researchers have also found that with lactation, breast cells are regularly shed and removed from the body. This shedding is believed to help remove cells with DNA damage that are more likely to develop cancer. Shedding these cells and the cellular changes that happen in the breast tissue throughout pregnancy and ongoing in lactation may bring about changes that are protective against cancer.

Lifestyle Factors May Contribute, Too 

Mother playing with her baby after a diaper changeMother playing with her baby after a diaper change

Lactation tends to inspire lifestyle choices that help prevent most types of cancers. Breastfeeding is often identified as a reason for more nutritious food choices, not smoking cigarettes, and healthy weight management.

Not a direct link, but sleep is so important to the body’s overall health and inadequate sleep is also thought to increase risk of cancers, including breast cancer. Having a baby in general means at least some disrupted sleep but breastfeeding can actually result in more sleep than not breastfeeding your baby. Yet one more way breastfeeding may lower the risk of breast cancer.

Does it Matter if You’re Nursing or Pumping? 

No. Whatever the exact causes of breastfeeding’s impact on breast cancer risk, the evidence is clear: both pre- and post-menopausal breast cancer risk goes down for those that breastfeed their babies. This normal risk reduction happens whether nursing directly or pumping in any combination.

Removing milk from the breasts on a consistent and regular basis triggers the hormonal changes that may be responsible for decreasing your chances of developing breast cancer. However, to improve the likelihood of lactation amenorrhea (no menstrual cycle during lactation), avoid your baby having any artificial nipples such as bottles or pacifiers and nurse responsively to your baby’s hunger cues.

Lower Risk Isn’t No Risk 

Mom, dad and baby relaxing together on the couchMom, dad and baby relaxing together on the couch

Breastfeeding can greatly reduce your breast cancer risk and when combined with other lifestyle factors such as:

  • Regular exercise
  • Sleep hygiene
  • Healthy diet
  • Avoiding BPAs, phthalates and other carcinogenic chemicals
  • Monthly self breast exams
  • Regular healthcare provider visits and recommended screenings

But, it is important to remember that lower risk doesn’t mean no risk. Knowing your own personal risk factors, such as family history, and being familiar with the symptoms of the different types of breast cancer are necessary for early detection – which, when combined with treatment, is associated with over a 90% survival rate. Learn how to perform regular self breast exams and do them monthly to increase your chances of detecting breast cancer early even if your chances are low.

There’s no way to completely eliminate your risk of breast cancer. But, given how much breastfeeding is a contributing factor in lowering breast cancer risk, lactation support is imperative for anyone who wants to breastfeed. The impact of systemic failures in lactation support is a public health concern for both the infants and their parents. By improving lactation education, support and sustainable social systems for breastfeeding parents, we improve public health.

If lactation isn’t an option for you, the good news is there are other ways to help lower your chance of developing breast cancer and every possible measure is helpful. Along with early detection, all measures you can take improve your chances of an optimal outcome.

Get more tips on breast cancer prevention here.

Drawing from a diverse background in the performing arts and midwifery Jessica Martin-Weber supports women and families, creating spaces for open dialogue. Writer, speaker and relationship and parenting coach, Jessica is the creator of, co-creator of, freelance writer and mom. Jessica lives with her family in the Pacific Northwest and co-parents her 8 daughters with her husband of 25 years.