Cancer diagnosis/treatment in the mother Breast-feeding can usually continue while diagnostic tests are undertaken. However, it is important to ensure that all health care professionals who are involved in the mother’s care know that she is breast-feeding. Chemotherapy and radiotherapy are both contraindicated for breast-feeding, but milk can be expressed before the mother starts treatment, so that the baby can continue to receive its benefits for as long as possible. During treatment, the mother can express (and discard) her milk, to maintain milk supply for resumption of breast-feeding when it is safe.

In mothers with a personal history of breast cancer Pregnancy, lactation and the accompanying highly-elevated plasma prolactin levels do not appear to increase the risk of breast cancer recurrence and will in some cases prolong survival.1 Guidelines on breast cancer, pregnancy and breast feeding, produced for physicians in Canada, may also be worth reading.2 Drugs used to treat specific cancers, including long-term treatments such as tamoxifen, are often contraindicated in pregnancy. In all cases, the mother who is receiving any drug treatment in association with a cancer diagnosis should not breast-feed unless she has clear advice from her oncologist that it is safe for the baby to receive breast milk.


  1. Bercovich D, et al. Pregnancy and lactation after breast cancer elevate plasma prolactin, do not shorten and may prolong survival. Med Hypotheses 2009; 73: 942-947
  2. Helewa M, et al. Breast cancer, pregnancy and breastfeeding. J Obstet Gynaecol Can 2002; 24: 164–180.

    From: Journal of Family Health Care Bulletin. Directory of Breast-Feeding Advice. December 2009. Published with JFHC 2009; 19(6).