Information About Pregnancy and Breastfeeding During and After Breast Cancer

Breast Cancer and Breastfeeding

Many women become pregnant before a breast cancer diagnosis or after treatment. However, some treatments may make pregnancy more difficult or prevent breastfeeding. Mothers and expectant mothers should discuss these issues with their doctor during and after treatment.

The median age at breast cancer diagnosis is 62. However, if you are a young woman with breast cancer, we will try to answer your questions about the effects and risks of this disease and its treatment on having children.

Can Breast Cancer Treatment Affect My Unborn Baby?

Chemotherapy, hormone therapy or targeted drugs are among the breast cancer treatments you should discuss with your doctor before becoming pregnant if you are receiving them. These medicines may affect a growing fetus, so waiting until all treatment is completed is safer. Stopping treatment early may also increase the risk of cancer growth or recurrence. However, if you wish to stop hormone therapy early to become pregnant, having received hormone therapy for at least 2 years after breast cancer surgery is recommended. Discuss the benefits and risks of stopping hormone therapy early for pregnancy with your oncologist.

- Related Topic: Information About Embryo Freezing and Infertility Treatment for Patients with Cancer

Can I Breastfeed After Breast Cancer Treatment?

If you have had breast surgery and/or radiotherapy, you may have breastfeeding difficulties in the treated breast. Studies show reduced milk production and potentially painful breastfeeding in that breast. Nevertheless, many women treated for breast cancer can breastfeed. Breastfeeding is not recommended while receiving chemotherapy or hormonal treatment, such as tamoxifenfor breast cancer.

- Related Topic: Breast Cancer During Pregnancy and Breastfeeding — Symptoms, Diagnosis and Treatment

Is Breastfeeding Safe During Chemotherapy?

No. For the baby's safety, breastfeeding during chemotherapy is not recommended. Many chemotherapy medicines, particularly cyclophosphamide and methotrexate, may appear in high concentrations in breast milk and harm your baby. Continuing to pump and discard milk can maintain milk production. Breastfeeding can resume when your oncologist considers it safe.

Does Not Breastfeeding Put Your Baby's Health at Risk?

Breast milk is, of course, the healthiest and least expensive way to feed a baby. However, many mothers already use formula because of health issues or insufficient milk. Mothers diagnosed with cancer should not feel guilty if unable to breastfeed or worry that their baby's development will suffer. A study in 2014 involving 1.773 siblings compared one breastfed sibling with another fed infant formula. It found no significant differences between the groups in any of 11 health problems, including obesity and asthma, or cognitive abilities, including mathematical ability and memory-based intelligence.

If you have any concerns about your baby's health during breast cancer treatment, talk with your doctor and ask for formula recommendations.

Should I Breastfeed Before and Immediately After Surgery?

No. If you are planning breast cancer surgery, stop breastfeeding to reduce breast blood flow. This reduces infection risk and helps prevent breast milk from collecting at biopsy or surgical sites.

If breastfeeding, pumping before surgery lets your baby continue receiving breast milk. You may need to wait before resuming breastfeeding after surgery because anesthetic drugs may pass into breast milk and harm the baby.

Can You Breastfeed During Radiotherapy?

Generally, it is not recommended. Radiotherapy requires asking your oncologist whether breastfeeding is safe during treatment. Safety may vary depending on the type of radiation and the body part being treated.

Can I Have a Baby After Breast Cancer?

Yes. Some breast cancer treatments may affect fertility, the ability to have children. For example, chemotherapy may damage the ovaries. Nevertheless, many women become pregnant after treatment. Discussing this before treatment allows necessary precautions.

Can Pregnancy and Breastfeeding Bring Breast Cancer Back?

No. Because many breast cancers are estrogen-sensitive, there are concerns that high hormone levels during pregnancy may increase recurrence risk. Studies show pregnancy does not increase the risk of cancer returning after successful treatment.

There is no evidence that breastfeeding after breast cancer treatment increases recurrence risk.

Should I Wait After Breast Cancer Treatment Before Becoming Pregnant?

Yes. Some doctors advise women wishing to have children to wait at least 2 years after all treatment ends before becoming pregnant. The optimal waiting period is unclear, and this advice is not based on a clinical trial. Some breast cancers can recur after 2 years, so every case differs. Factors such as age, desire for pregnancy, cancer type and recurrence risk must be considered.

If I Become Pregnant, Does My History of Breast Cancer Put My Baby at Risk?

There is no evidence that a woman's breast cancer history directly affects her baby. Scientists have found no increase in birth defects or other long-term health problems among children of women with breast cancer. However, approximately %10 of breast cancers are inherited. If your cancer belongs to this %10 group, this should be considered when monitoring your child's cancer risk in adulthood.

- Related Topic: How Should People with Hereditary Breast Cancer Be Monitored and Treated?

Talk with Your Doctor

If diagnosed with breast cancer and you have a baby or are considering having one, discuss with your doctor how treatment may affect breastfeeding and your chances of pregnancy. This assessment should include the risk of cancer recurrence. 

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- Recommendations for Menopausal Symptoms After Breast Cancer