Does Breastfeeding Reduce Your Risk of Breast Cancer?

Breastfeeding has been shown to have some protective effect against breast cancer. Studies have found that women who breastfeed for a longer duration have a lower risk of developing breast cancer compared to women who do not breastfeed at all or breastfeed for a shorter duration.

The exact reason why breastfeeding can reduce the risk of breast cancer is not fully understood, but it may be related to the fact that breastfeeding causes changes in breast tissue that make the cells less susceptible to becoming cancerous. Breastfeeding also suppresses ovulation and estrogen production, which are known to play a role in the development of breast cancer.

However, it is important to note that breastfeeding alone cannot completely prevent breast cancer. Other factors, such as genetics, age, and lifestyle, can also increase a person’s risk of developing breast cancer. Women who are concerned about their risk of breast cancer should talk to their healthcare provider about their individual risk factors and ways to reduce their risk.

Breast cancer is the most common cancer affecting women. The American Cancer SocietyTrusted Source estimates that 1 in 8 women, about 13%, will receive a breast cancer diagnosis at some point in their lifetime.

While there’s no sure way to prevent breast cancer, there are some things that can reduce your risk. For example, did you know that breastfeeding can reduce your risk of breast cancer?

2020 survey studyTrusted Source conducted in the United States found that only 38.5% of the women that were surveyed were aware that breastfeeding reduces breast cancer risk.

Read on to learn more about how breastfeeding lowers your risk of developing breast cancer, other steps you can take to prevent breast cancer, and more.

How does breastfeeding lower your risk of breast cancer?

Breastfeeding can lower the risk of breast cancer through several mechanisms.

Firstly, breastfeeding causes structural changes in the breast tissue that make it less susceptible to cancer development. During breastfeeding, breast cells mature and differentiate, which reduces the number of immature cells that could potentially become cancerous. Additionally, lactation temporarily suppresses ovulation and reduces exposure to the hormone estrogen, which can promote the growth of certain types of breast cancer.

Secondly, breastfeeding may help eliminate cells with DNA damage or mutations, which could otherwise lead to cancer. Studies have shown that lactation increases the turnover of breast cells, which means that damaged cells are more likely to be shed from the breast tissue.

Thirdly, breastfeeding has been associated with changes in the immune system that may help prevent cancer. Breast milk contains immune cells and antibodies that can help protect infants from infections. It’s possible that these same components could help protect the breast from cancer by boosting the immune response to cancer cells.

Overall, the evidence suggests that breastfeeding can modestly lower the risk of breast cancer, especially if a woman breastfeeds for a longer duration. The protective effect may last for several years after breastfeeding ends.

Research into breastfeeding and breast cancer risk

There have been numerous studies that have investigated the relationship between breastfeeding and breast cancer risk. Here are a few examples:

  • A meta-analysis of 27 studies found that women who breastfed for a longer duration had a lower risk of breast cancer than those who breastfed for a shorter duration or not at all. The protective effect was greatest for women who breastfed for a total of 12 months or more.
  • A large prospective study of more than 30,000 women found that those who breastfed for a total of 18 months or more had a 4.3% absolute reduction in their risk of breast cancer compared to those who did not breastfeed.
  • Another large prospective study of over 160,000 women found that each additional year of breastfeeding was associated with a 4.3% reduction in the risk of developing invasive breast cancer.
  • A study that followed over 500,000 Chinese women for a period of 10 years found that women who breastfed for at least 12 months had a 10% lower risk of developing breast cancer compared to those who did not breastfeed.

Overall, these studies and others suggest that breastfeeding can modestly reduce the risk of breast cancer. However, it’s important to note that breastfeeding is just one of many factors that can affect a woman’s risk of breast cancer, and other factors such as age, family history, and lifestyle habits also play a role.

What are the other benefits of breastfeeding?

The decision of whether or not to breastfeed is very personal. However, if you’re able to breastfeed, it’s worth considering. In addition to reducing your risk of breast cancer, it also has several other benefits as well.

According to the Centers for Disease Control and Prevention (CDC)Trusted Source, breastfeeding benefits you by reducing your risk of:

  • high blood pressure
  • type 2 diabetes
  • ovarian cancer

In addition to providing your baby with nutrition, breastfeeding can benefit your baby by reducing their risk of:

  • respiratory, ear, and gastrointestinal infections
  • type 1 diabetes
  • obesity
  • asthma
  • sudden infant death syndrome (SIDS)
  • necrotizing enterocolitis, a serious intestinal condition that can affect preterm babies
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What other things can you do to lower your risk of breast cancer?

In addition to breastfeeding your children, if possible, there are also other steps that you can take to help lower your risk of breast cancer.

Stay physically active

Regular physical activity can help to lower your risk of breast cancer as well as some other cancers. It’s also important for your overall health.

The Physical Activity Guidelines for AmericansTrusted Source recommends 150 to 300 minutes per week of moderate-intensity exercise, 75 to 150 minutes per week of vigorous-intensity exercise, or an equivalent combination of the two exercise types.

Manage your weight, if necessary

A higher body weight has been linkedTrusted Source to the development of several cancers, including breast cancer. As such, if you have overweight or obesity, talk with a doctor about healthy ways to manage your weight.


Reduce alcohol consumption

Alcohol, especially in excess, increases your riskTrusted Source of breast cancer and can have a variety of other negative health effects as well. In order to reduce your risk, consider reducing alcohol consumption or eliminating it entirely.

If you do choose to drink, the Dietary Guidelines for AmericansTrusted Source recommend one drink or less per day for women and two drinks or less per day for men. Keep in mind that what’s considered a drink varies by the type of alcohol.

Talk with a doctor

If you have a family history of breast cancer, talk with a doctor. They may suggest genetic testing to see if you have gene changes that significantly boost your risk. If so, you can explore further preventive options like medications or surgery.

Taking certain hormone-based medications like oral contraceptives and hormone replacement therapy also increases your breast cancer risk. If you take these medications, talk with a doctor about the pros and cons of these medications and if there are any alternatives.

What are the primary causes and risk factors for breast cancer?

Breast cancer happens when cells in the breast begin to grow and divide uncontrollably, potentially spreading to other areas of the body. It happens due to changes to genes in your DNA that affect the way that cells grow and divide.

Some of these genetic changes happen because of random errors that occur as your cells divide. Others may be passed down, or inherited, from your parents. Certain lifestyle and environmental factors can also promote genetic changes.

Known risk factors for breast cancer

Things that increase your risk of developing a condition like cancer are called risk factors. The known risk factors for breast cancer include:

  • being an older age
  • having a personal or family history of breast cancer
  • inheriting certain genetic changes, such as those in the BRCA1 and BRCA2 genes
  • having dense breasts
  • having certain benign breast conditions like:
    • lobular carcinoma in situ (LCIS)
    • fibroadenoma
  • having certain other health conditions, such as obesity or type 2 diabetes
  • starting your menstrual period at an earlier age
  • experiencing menopause at an older age
  • not having children or having your first child at a later age
  • not breastfeeding
  • using certain hormone medications, such as oral contraceptives and hormone replacement therapy
  • receiving radiation therapy to your chest
  • being a taller height
  • consuming alcohol
  • having low levels of physical activity
How often should you receive screening for breast cancer?

Breast cancer screening can go a long way in detecting breast cancer in its early stages. When it’s found early, the outlook for people with breast cancer is better.

The test that’s typically used for breast cancer screening is called a mammogram. In some scenarios, breast MRI or breast ultrasound may also be used as a part of screening.

The American Cancer SocietyTrusted Source recommends the following for women at an average risk of breast cancer:

  • Age 40 to 44: Consider having a screening mammogram every year.
  • Age 45 to 54: Receive a screening mammogram each year.
  • Age 55 and older: Consider having a screening mammogram every other year or continue to have them yearly.

Those at a high risk of breast cancer are recommended to begin screening with a breast MRI and a mammogram starting at age 30. This includes:

  • people with a strong family history of breast cancer
  • individuals with known genetic changes that increase breast cancer risk
  • those who’ve received radiation therapy to their chest

Screening recommendations can vary between organizations

Screening recommendations can vary according to the organization issuing them. For example, the National Comprehensive Cancer Network and the U.S. Preventive Services Task Force have slightly different recommendations.

As such, it’s always a good rule of thumb to have an open conversation with a doctor about your individual breast cancer risk. They can help recommend screening times and methods that are right for you.

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Frequently asked questions about breastfeeding and breast cancer

How long do you need to breastfeed in order to get the most benefits?

Generally speaking, people who breastfeed for longer than a year receive the most benefits. However, it’s still possible to get some benefits if you breastfeed for less than a year.

Can you still get breast cancer if you breastfeed? How common is it?

Yes. However, it’s uncommon during your childbearing years. The American Cancer SocietyTrusted Source notes that breast cancers in women under age 40 are estimated to make up only 4% of new invasive breast cancer diagnoses in 2022.

Getting breast cancer while breastfeeding is also rare. According to 2012 researchTrusted Source, It’s estimated that only 3% of women develop breast cancer while breastfeeding.

Does having children decrease your risk of breast cancer (even if you don’t breastfeed them)?

Yes, the risk of breast cancer tends to decrease with the number of births. However, some research indicates that this effect varies between different types of breast cancer.

Can breastfeeding lower the risk of ovarian cancer?

Yes. Some researchTrusted Source has found that breastfeeding for over 12 months can reduce the risk of ovarian cancer by 37%.

How many women breastfeed?

According to the CDCTrusted Source, 83.2% of babies born in 2019 were breastfed. This number dropped to 55.8% and 35.9% at 6 months and a year, respectively.


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