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Breast Feeding after Receiving Chemotherapy During Pregnancy

By: Elyce Cardonick, MD (published in Hopeline newsletter Fall 2013)

Many women ask about the safety of breast feeding after a pregnancy complicated by cancer. Let me start by saying that if you do require any chemotherapy postpartum, unfortunately breast feeding is not advised once you start treatment. There are case reports of children having neutropenia (low white counts) after receiving breast milk while a mother was receiving Cytoxan. There is not much information on the quantity of other types of chemotherapy in breast milk, but it is not advised.

If however you have completed chemotherapy during pregnancy, or if you don’t need to start chemotherapy immediately postpartum, breast feeding may be an option.

For women who receive chemotherapy during pregnancy, at least 3 if not 4 weeks are suggested between this treatment during pregnancy and delivery. If this amount of time has passed between your last chemotherapy treatment and delivery, you may be able to breast feed safely if you are not restarting chemotherapy postpartum. Ask your doctor about the half life of the chemotherapy agent and if it has any active metabolites. Take the longest half life X7 and that should be the elimination time for the chemotherapy drug. For example, for Cytoxan, the half life is 1.3-16 hours, so it would be safe to breast feed 5 days after treatment. For Adriamycin, the half life is 24 hours, but there is metabolite with a half life of 48 hours, so after 14 days it would be safe to breast feed.

We followed the breast feeding experience of 88 women diagnosed with cancer during pregnancy who did not have a contraindication for breast feeding. The following is not to discourage women with a diagnosis of cancer during pregnancy to try breast feeding, but to be aware of realistic expectations to curb disappointment or “baby blues.”  Of the 88 women who attempted breast feeding women, up to 57% reported breast feeding issues. Of these, 96% received chemotherapy: 11% less than 4 cycles; 88.9% at least 4 cycles. In the group reporting successful breast feeding, 63% received chemotherapy: 35% < 4 cycles; 65% at least 4 cycles. Statistically, testing was used for comparisons. The mean number of chemotherapy cycles during pregnancy was statistically less in the group without breast feeding issues. Gestational age in pregnancy at the time of the first treatment was significantly earlier in the group experiencing difficulty breast feeding 18.5 weeks versus 22 weeks. Neither the gestational age at the last treatment, nor the duration from final treatment to delivery was a significant factor affecting breast feeding problems.

Breast milk is known to provide the most beneficial nutrition and immune support to newborns. Mothers that breast feed their infants provide them with essential nutrients and immunoprotection from pathogenic bacteria and improve the integrity of the gastrointestinal tract. In addition, infants who are breast fed have less risk of asthma, atopic allergies, and obesity.  It’s worth a try if it is important to you, but don’t feel badly if it’s not successful or possible due to a need for further treatment. Most importantly, have the treatment you need to be a healthy mom for your newborn. There are breast milk banks available for donated milk if desired or ask your pediatrician for a recommendation for the best formula for your child.