Is Breastfeeding Safe With Breast Cancer?

The possibility and safety of breastfeeding when you have breast cancer depends on where you are in your journey and what treatments you are receiving. While your oncologist telling you that you need stop breastfeeding may not be what you want to hear, there may be times when doing so is what's best for both your health and that of your baby.

Mom breastfeeds newborn baby
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Breastfeeding at Diagnosis

Because cancer is difficult to detect in a lactating breast, it is unusual—though not impossible—for women to be diagnosed during the time they are breastfeeding.

Should this happen, it does not automatically mean the end of breastfeeding. For example, diagnostic procedures (such as a needle biopsy) do not generally pose an obstacle to continued breastfeeding.

At this point, you may want to pump and store breast milk, or research and select a baby formula, so you can bridge the gap if your treatment regimen ends up requiring you to put breastfeeding on hold.

Breastfeeding During Treatment

If your treatment involves surgery, find out whether the surgeon has operated on a lactating breast before, as it can be complicated. While you do not want to harm the milk ducts unnecessarily, removing the cancer may involve some damage. That would be the only part of surgery that would affect you being able to breastfeed.

However, if your treatment plan includes chemotherapy, you will need to discontinue breastfeeding during the course of treatment and for some time thereafter. Chemotherapy agents are passed on through breast milk and may be toxic to your child.

Radiation therapy may also require an interruption in breastfeeding, depending on the type of radiation used and the duration of treatment. Your healthcare provider will be able to explain the effects of your treatment and whether you can breastfeed using both breasts or only the unaffected breast while treatment is underway.

If you have been advised by your healthcare provider not to breastfeed during treatment because the safety of your milk may be in doubt, you might choose to adopt a "pump and dump" routine. This involves pumping the breasts each day so the milk supply continues, but discarding the milk. Once your milk supply is considered safe again, you can resume breastfeeding as normal.

Breastfeeding After Treatment

When your treatment has ended, you and your baby may be able to pick right up where you left off, or you may need a bit of patience and perseverance to get back on track. Remember that the effects of your treatment may still linger in your body and your breast milk. Ask your healthcare provider when it is safe to try breastfeeding again.

After surgery, breastfeeding may be a challenge. Surgery may have damaged some of your milk ducts, reducing the amount of milk you are able to provide. If you were breastfeeding (or planning to) before your surgery, your surgeon may have sought to avoid duct damage where possible. But even if damage has occurred, diligent nursing may bring your supply back up within a few weeks, or the unaffected breast may increase its production sufficiently to make up the difference.

Your milk supply may be diminished or eliminated in the treated breast after radiation therapy. Radiation may also decrease the elasticity of the nipple, making it harder for your infant to "latch on" properly. If you find that the treated breast is not working, your other breast should be able to make up the missing volume of milk on its own within a couple of weeks of resuming regular nursing.

After chemotherapy, residual chemicals may still be present in your milk supply. Ask your healthcare provider when it is safe to breastfeed again. The good news is that once you have been cleared by your practitioner, chemotherapy is unlikely to have any long-term effect​ on your ability to breastfeed.

If you are prescribed ongoing Nolvadex (tamoxifen) therapy, you will not be able to breastfeed until after you have stopped this course of treatment. Tamoxifen inhibits the production of milk and its presence in any remaining breast milk could be harmful to the child.

Recurrence Risk

A common question among breastfeeding cancer survivors is whether the hormones of pregnancy and lactation could trigger a recurrence of the disease. There is no evidence for this. In fact, some research indicates that breastfeeding may actually lower a woman's risk of breast cancer, though the studies have not addressed recurrence in women who have already been diagnosed.

Getting Support

Breastfeeding is not easy, even in the best of circumstances, and a diagnosis of breast cancer multiplies the difficulties. In addition to sharing your plans to breastfeed with your cancer treatment team, you will want to consult your obstetrician and your child's pediatrician.

Moreover, because the challenges can be psychological and emotional, as well as physical, you might find it helpful to speak with a mental health professional who can help you work through issues involving body image or the loss of control you may feel.

Also, consider enlisting the help of a certified lactation consultant. These trained clinical professionals can provide assistance with special situations, such as expressing milk and storing it for later use, or maintaining milk supply during an interruption in your breastfeeding routine.

If your cancer treatment center is affiliated with a hospital that has a birth center, the staff may be able to recommend a lactation consultant. The International Lactation Consultant Association may be able to provide additional information about locating a lactation consultant near you, too.

A Word From Verywell

Given the known benefits of breastfeeding, being diagnosed with breast cancer is not necessarily a reason to stop completely, but it's very important to talk with your oncologist about the safest way to proceed given your specific treatment plan. There is no evidence that breast milk from a cancer survivor poses any risk to an infant, so long as any residual effects of treatment have cleared the system.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Memorial Sloan Kettering Cancer Center. Can I Breast-feed during Cancer Treatment?

  2. American Cancer Society. Pregnancy After Breast Cancer.

  3. Kotsopoulos J, Lubinski J, Salmena L, et al. Breastfeeding and the risk of breast cancer in BRCA1 and BRCA2 mutation carriersBreast Cancer Res. 2012;14(2):R42. Published 2012 Mar 9. doi:10.1186/bcr3138

By Lia Tremblay
Lisa Tremblay is an award-winning writer and editor, writing for magazines, websites, brochures, annual reports, and more for over 15 years.