The short answer
Some cancer treatments are not safe during breastfeeding because the drugs can reach the baby through breast milk. Chemotherapy is one example. Other treatments and situations may allow feeding to continue or pause. Your care team can help you plan feeding around your treatment safely.
Some cancer drugs can pass into breast milk and reach the baby.
People receiving chemotherapy are advised not to breastfeed.
Certain surgeries may lead a doctor to suggest stopping breastfeeding first.
Decisions about feeding depend on the treatment, so ask your team about your plan.
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The full explanation.
The simple version
If you are being treated for cancer and have a baby, you may wonder whether it is safe to breastfeed. The honest answer is that it depends on your treatment. Some treatments are safe with feeding, and some are not.
The main concern is simple. A few cancer treatments can pass into breast milk. If that happens, the baby would take in the drug. To keep the baby safe, doctors sometimes advise pausing or stopping breastfeeding during treatment.
Whether you can breastfeed depends on which treatment you are getting.
Chemotherapy and breastfeeding
Chemotherapy uses drugs to kill cancer cells. NCI advises that people receiving chemotherapy should not breastfeed. Many chemotherapy drugs can build up to high levels in breast milk and could harm a nursing baby.
This does not mean feeding is off the table forever. It means that while chemotherapy is being given, breastfeeding is not safe.
During chemotherapy, breastfeeding is not recommended.
Other treatments
Chemotherapy is not the only treatment that can reach a baby through milk. Hormone therapy, targeted therapy, and immunotherapy are also generally not given to someone who is nursing, because they can be harmful to a baby.
Surgery is a little different. If breast surgery is planned and you have already given birth, your doctor may suggest stopping breastfeeding beforehand. This helps lower blood flow in the breasts and make them smaller, which can help with the operation.
Several treatments call for a pause in breastfeeding, each for its own reason.
Making a feeding plan
Because the answer depends on your treatment, the best step is to ask your care team directly. They can tell you whether feeding is safe now, whether you should stop, and when.
It also helps to know that stopping breastfeeding is not a treatment for the cancer itself. NCI notes that stopping lactation does not necessarily improve a person's chance of survival. Feeding decisions are made mainly to protect the baby during treatment, not to change the cancer.
A quick conversation with your team gives you a clear, safe plan.
The feelings that come with it
For many people, feeding a baby is deeply personal. Being told to stop, even for a while, can bring sadness, guilt, or stress. Those feelings are understandable.
You do not have to manage them alone. A social worker, counselor, or support group can help. Your care team can also point you to feeding support and other resources so both you and your baby are cared for.
Your feelings about feeding are valid, and support is there for them.
When to get help sooner
- Call your care team immediately, at any hour, if a fever of 100.4°F (38°C) or higher arrives while you are on chemotherapy. CDC treats fever during chemotherapy as a medical emergency (CDC). If they cannot be reached quickly, go to an emergency department and say you are on chemotherapy.
- Call 911 or go to an emergency department if you feel confused or faint, your breathing quickens, or you are shaking uncontrollably, whether or not a breast is involved.
- Call your care team the same day if a patch of breast turns red, hot, and sore while you are weaning or pumping, especially with a temperature of 100.4°F (38°C) or higher, chills, or an achy flu-like feeling. That combination suggests a breast infection, and it is treated with antibiotics (MedlinePlus). If chemotherapy is under way, use the emergency route above instead.
- Call your care team the same day if your baby fed after a chemotherapy, targeted therapy, or immunotherapy dose by mistake. Say what drug and when, so someone can advise you about the baby rather than leaving you to guess.
- Call your care team within a day or two if the breasts stay hard and painfully full after you stop feeding, or a tender lump does not soften. There are ways to ease engorgement safely alongside your treatment.
- Call your care team within a day or two if the sadness or guilt about stopping is not lifting. Ask for the social worker by name; that referral exists for exactly this.
Words to know
Tap any term to see what it means.
Common questions
Can I breastfeed while getting chemotherapy?
No. NCI advises that people receiving chemotherapy should not breastfeed. Many chemotherapy drugs can be found in high levels in breast milk and could harm a nursing baby.
Why do some cancer treatments affect breastfeeding?
Some drugs used to treat cancer can pass into breast milk. Because a nursing baby would then take in the drug, treatments like chemotherapy, hormone therapy, targeted therapy, and immunotherapy are generally not given to someone who is breastfeeding.
Does surgery affect breastfeeding?
It can. If breast surgery is planned and the person has already given birth, doctors may advise stopping breastfeeding first. This helps reduce blood flow in the breasts and make them smaller for surgery.
Will stopping breastfeeding improve my chance of survival?
Not on its own. NCI notes that stopping lactation does not necessarily improve a person's chance of survival, though this depends on the type and stage of cancer. Feeding decisions are made mainly for the baby's safety during treatment.
Can I breastfeed after treatment ends?
That depends on your treatment and your body, and it is a good question for your care team. Some people are able to breastfeed later, while others are not. Your team can give you the clearest answer for your situation.
Questions to ask your doctor
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Last updated: 2026-08-18Next planned review: 2028-07-14
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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