If you are a breast cancer survivor expecting a new baby, you may have questions or concerns about breastfeeding. Most women deliver healthy babies after cancer treatment however, breastfeeding can be impacted, so it is helpful to understand the possible challenges ahead. With the guidance of your healthcare team, including an International Board Certified Lactation Consultant (IBCLC), you can set realistic expectations to reach your personal breastfeeding goals. 

Can I Breastfeed After Breast Cancer?

Breastfeeding success varies depending on your treatment plan, history of breast surgery, and medications administered. Every survivor's journey is unique. Since breastfeeding can decrease the risk of breast cancer recurrence and provide other health benefits, researchers often suggest that mothers who have undergone cancer treatment consider breastfeeding.

Breastfeeding has many short and long-term health benefits for women, and protection against breast cancer might be stronger than you think. According to the National Institutes of Health the risk of breast cancer decreases by 4.3% for every 12 months of breastfeeding. Additionally, abrupt involution of the mammary glands when mothers do not breastfeed can increase inflammation and ductal changes, which are known risk factors for breast cancer. These can be encouraging statistics for young breast cancer survivors.

Genetic Risks for Breast & Ovarian Cancer

A BRCA gene helps suppress tumor growth. Everyone has these genes, but if a BRCA gene is mutated, your risk of cancer—including breast and ovarian cancer—increases. The good news is that carriers of a BRCA mutation receive the same protective effects as non-carriers. Research shows that the longer at-risk mothers breastfeed, the lower their cancer risk. Breastfeeding for 7 months or longer can reduce ovarian cancer risk by up to 32% compared to those who had never breastfed at all.

Breast Cancer Treatment & Effects

Surgery

Breast cancer surgery can damage the milk ducts and affect the amount of milk you can produce. After a lumpectomy, depending on how much tissue was removed, some milk may still be produced on the treated breast. After a partial mastectomy, breastfeeding on the unaffected breast is possible. With a bilateral mastectomy, all ducts are removed, and milk production is not possible. Nipple-sparing surgery sometimes allows very small amounts of milk to be synthesized, though supplementation will be necessary.

Discuss breastfeeding goals preoperatively with your surgeon. The type of surgery, proximity of the incision to milk-making ducts, and preservation of breast tissue and nerves all influence future milk production.

Radiation Treatment

Radiation therapy can cause permanent damage to the breast tissue, reducing your ability to make enough milk. You may also be more susceptible to mastitis on the radiated breast, which may be harder to treat with antibiotics after radiation. While there are no absolute contraindications to breastfeeding, mothers should be aware of the potential risks of skin breakdown or abrasions due to radiation-induced inelasticity of the nipple areola complex.

Chemotherapy Drugs

Healthcare providers will advise you to wait to breastfeed after chemotherapy, but the timeline can vary from just a few days to months depending on the type of medication you have received. Communication with your healthcare team is very important as you prepare to breastfeed and navigate any challenges that may arise, ensuring the safest plan for both you and your baby.

Immunotherapy & Hormone Therapy

Targeted immunotherapy with monoclonal antibodies such as trastuzumab or pertuzumab is not recommended during pregnancy. In many cases, treatment can be resumed postpartum. Breastfeeding is generally not recommended during immunotherapy and for at least seven months after the last dose. Your healthcare team can help you plan the safest timing for resuming breastfeeding once treatment is complete.

Medications used for long-term hormone modulation—such as tamoxifen and aromatase inhibitors—can pass into human milk and may be harmful to the baby. Breastfeeding is contraindicated while taking these medications.

Support For Breastfeeding After Breast Cancer

The actual effects your cancer treatment will have on breastfeeding will not be fully clear until your baby is born and you begin producing milk. Many factors—including the time of diagnosis, type of treatment, and whether you had a healthy breast unaffected by surgery or radiation—can influence feeding outcomes. Like cancer, breastfeeding is a personal journey, and you will have options to decide what best supports baby’s health and your own well-being.

Supply & Demand

Making milk works on supply and demand. Breastfeeding frequently from the start will get your milk supply off to a healthy start. Frequent milk removal—whether by breastfeeding or using a breast pump—encourages ongoing milk production. If supply is low on the affected breast, but strong on the other, it is possible to breastfeed on just one side. It is important to monitor your baby to ensure proper weight gain in the early weeks postpartum, especially if feeding from only one breast.

Every Drop Counts

Breastfeeding is not all or nothing. Any amount of milk you can provide will be beneficial for your baby. The vast majority of women who choose to breastfeed after breast cancer find that some level of breastfeeding or milk production is possible, even if only partial.

Deciding Not to Breastfeed

If you decide not to breastfeed, gradual weaning is recommended to avoid complications from abrupt weaning. Work with your lactation consultant to safely reduce milk production and protect your physical and emotional health. If you are currently taking any cancer-related medications, speak to your doctor before breastfeeding. 

What if I Get Diagnosed While Pregnant or Breastfeeding?

Receiving new information about a breast cancer diagnosis during pregnancy or while breastfeeding can feel overwhelming. In general, most types of diagnostic radiography and contrast agents do not require separation of mother and baby, and breastfeeding can often continue until you decide on a treatment plan.

The Academy of Breastfeeding Medicine's (ABM) “Find a Physician” Tool is a good place to locate a healthcare provider with breastfeeding medicine expertise who can help guide you through this period safely. The ABM Clinical Protocol guidelines offer evidence-based recommendations for managing breastfeeding during cancer evaluation and treatment, helping you and your care team make informed, supportive decisions that protect both your health and baby’s health.

Looking Ahead with Hope

Welcoming a new baby after a history of breast cancer can bring a mix of emotions, but you are not alone on this path. With compassionate guidance from your care team and strong postpartum support from your partner and family members, many mothers find meaningful ways to nourish and bond with their babies. Whether you provide a little or a lot of breast milk, your efforts matter. What truly counts is the love, presence, and resilience you bring to your baby’s life. You have already overcome so much—and this next chapter can be filled with hope, connection, and confidence in the choices that are right for you.

Disclaimer: Our classes and accompanying materials are intended for general education purposes and should not replace medical advice. For personalized recommendations, please consult your healthcare provider and/or lactation consultant.