Biologic Medications and Breastfeeding Your Baby

There are varying levels of evidence on the use of biologics in nursing moms

During pregnancy and breastfeeding, many women are concerned about the medications they are receiving and how they will affect a growing fetus and infant. A class of medications called biologics are becoming more commonly used to treat inflammatory conditions and some types of cancers. These medications are large molecules that are derived from living cells. They are given either by infusion in a hospital, infusion center, or physician's office or are given by injection either at home or in a doctor's office.

The effectiveness of biologics in treating certain diseases and conditions has been beneficial for patients. However, because they are a newer class of medications, and there may not be as much evidence available on use during pregnancy and breastfeeding, there can be some concern for parents. This article will examine the evidence of safety during breastfeeding for some common biologic medications.

The answers to questions about medications and breastfeeding aren’t always easy to find. It’s important to consult all the members of a healthcare team, including the obstetrician and pediatrician, about changes to medication and the effects medications may have on a breastfed infant. The risks and benefits to the mother and the baby, and the protection of the nursing relationship, are all important considerations when making decisions about medication.

Breastfeeding woman and child
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Avastin (bevacizumab)

Avastin is a medication given by infusion to treat certain types of colorectal cancer in conjunction with other medications. It’s not known if, or how much, Avastin passes into human milk. Other, similar medications do pass into breastmilk but it’s not thought that they are taken up by the infant’s digestive system in “substantial” amounts. The manufacturer recommends avoiding breastfeeding while receiving treatment and for 6 months after the last dose.

Another source recommends caution, especially when breastfeeding a premature infant. There have been some case reports of breastfeeding mothers receiving Avastin injected into the eye for treating eye conditions (the drug is indicated for wet age-related macular decline and macular edema). There were no reported adverse events in these nursing parents. However, there is a concern that Avastin could suppress milk production.

Avonex (interferon beta-1a)

Avonex is an injectable medication that is approved to treat multiple sclerosis. The amount of Avonex that is passed into breastmilk is known to be “minuscule.” It is also not well absorbed orally and therefore would not be taken up in large amounts by a nursing infant. There is a general consensus that Avonex can be used by nursing mothers. One study showed that infants breastfed by women with multiple sclerosis who received Avonex did not experience any adverse reactions.

Cimzia (certolizumab pegol)

Cimzia is an anti-TNF medication that is approved to treat Crohn’s disease, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, and plaque psoriasis. Cimzia is self-injected. It’s estimated that the amount of Cimzia that passes into human milk is only about .15% of the amount that is in the mother’s blood. A level of less than 10% is not thought to be a concern. Cimzia isn’t thought to be taken up well in the digestive system, which means that an infant will probably not absorb it. It’s currently thought that women can continue Cimzia while breastfeeding.

Cosentyx (secukinumab)

Cosentyx is an injectable medication approved to treat plaque psoriasis, psoriatic arthritis, and ankylosing spondylitis. It is a large molecule and is therefore thought to pass into human milk in small amounts, but there is currently no clinical evidence. It is also thought it would not be absorbed in an infant’s digestive tract. The manufacturer recommends weighing the benefits and risks when making decisions regarding the use of Cosentyx in breastfeeding mothers. They recommend using caution especially in the case of a premature infant.

Enbrel (etanercept)

Enbrel is given by injection and is approved to treat rheumatoid arthritis, polyarticular juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, and plaque psoriasis. While there are no data available on infants breastfed by mothers receiving Enbrel, it’s thought that the amount that is passed into human milk is low. A case report of two breastfeeding mothers with rheumatoid arthritis receiving Enbrel showed that the drug level in human milk was “negligible." Other small studies show the same result. It’s recommended that the risks and benefits of the medication for the mother are taken into account by healthcare providers when making decisions regarding breastfeeding.

Herceptin (trastuzumab)

Herceptin is approved to treat HER2-overexpressing breast cancer and HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma (stomach cancer) and is given by infusion. There is no data available regarding the amount of Herceptin that passes into human milk or the effects on an infant. It’s thought that Herceptin does pass into human milk but that the amounts of the drug a baby might receive and take up are not substantial. The manufacturer recommends weighing the known benefits of breastfeeding, the mother's need for Herception therapy, and the drug's long, seven-month, washout period when deciding on receiving this medication while breastfeeding.

Humira (adalimumab)

Humira is a self-injectable medication that is approved to treat several different autoimmune conditions, including rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis, Crohn’s disease, ulcerative colitis, plaque psoriasis, hidradenitis suppurativa, and uveitis. It’s estimated that the amount of Humira that passes into human milk is low; between 0.1% and 1% of the amount that is found in the mother’s blood. Humira isn’t taken up well in the digestive system so it’s thought that an infant would not be exposed to even those low levels in their mother’s milk. Premature infants may absorb more of the medication than full-term infants. It’s currently thought that Humira is safe during breastfeeding.

Lantus (insulin glargine injection)

Lantus is a biosynthetic form of insulin that is used to treat type 1 diabetes and type 2 diabetes. Good blood sugar control is important to promote lactation. Lactating mothers who live with diabetes may require insulin to effectively manage their condition. Insulin is a normal part of breastmilk and receiving insulin is generally considered safe for nursing mothers and their infants. It is important for women with diabetes to ensure that their blood sugar is well-controlled in order to avoid a delay in milk production after birth.

Lucentis (ranibizumab)

Lucentis is an injection that is given in the eye to treat neovascular (wet) age-related macular degeneration, macular edema following retinal vein occlusion, diabetic macular edema, diabetic retinopathy, and myopic choroidal neovascularization. It’s thought that Lucentis passes into breast milk in very low amounts and that it would not be taken up in an infant’s digestive system. The manufacturer still recommends using caution in administering this medication in lactating women. However, the benefits for the mother need to be weighed against the potential risks.

Neulasta (pegfilgrastim)

Neulasta is an injectable medication that helps increase the white blood cell count in those who have experienced a drop in their white blood cell count because of anti-cancer drugs or radiation. The amount of Neulasta that is excreted in breastmilk is not well-studied but it’s thought that the levels are low based on research done on other filgrastim products. It is not absorbed orally by infants so it’s currently thought that it would not have any adverse effects on infants whose mothers are receiving the drug. The needs of the mother and the benefits of breastfeeding should be weighed against any potential risks.

Remicade (infliximab)

Remicade is a biologic medication that is given by infusion. It is approved to treat Crohn’s disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis. Research on levels in human milk has shown that Remicade is either undetectable or present in low amounts. There are several case reports of nursing infants whose mothers receive Remicade either having low or undetectable levels. A large multi-center study showed no differences in growth, development, or infection rate of infants whose mothers received Remicade when compared to infants whose mothers were not treated.

Rituxan (rituximab)

Rituxan is given through an intravenous infusion. It is approved to treat non-Hodgkin lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis (in conjunction with methotrexate), granulomatosis with polyangiitis (Wegener’s granulomatosis), microscopic polyangiitis, and pemphigus vulgaris. It is currently not known if Rituxan passes into breastmilk. The prescribing information advises that breastfeeding is not recommended while receiving this medication and for six months after having the last dose. However, it’s currently thought that Rituxan would not be taken up in the infant’s digestive tract. There are two case reports of breastfed infants who did not show any effects, although there’s no data available on long-term use. Another source recommends caution in breastfeeding mothers but also indicates that a currently nursing mother starting on Rituxan should not need to discontinue the medication.

A Word From Verywell

In all cases, it is important to consult an obstetrician and a pediatrician about medications during breastfeeding. Lactation consultants and other specialists who have experience in prescribing these drugs (such as gastroenterologists, rheumatologists, and neurologists) will also have knowledge and experience in their use during breastfeeding. The choice of medication is an individual decision and the mother’s health, as well as the baby’s, should be taken into account. In some cases, it’s clear that a breastfeeding mother may need to make a medication change but in others, it will require shared decision-making with the healthcare team. In all cases, the benefits of breastfeeding and the health of mother and baby will need to be weighed against any potential risks.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Genentech. Avastin highlights of prescribing information.

  2. Drugs and Lactation Database (LactMed). Bevacizumab.

  3. Drugs and Lactation Database (LactMed). Interferon beta.

  4. Clowse ME, Förger F, Hwang C, et al. Minimal to no transfer of certolizumab pegol into breast milk: results from CRADLE, a prospective, postmarketing, multicentre, pharmacokinetic study. Ann Rheum Dis. 2017;76:1890–1896. doi:10.1136/annrheumdis-2017-211384

  5. Drugs and Lactation Database (LactMed). Secukinumab.

  6. U.S. National Library of Medicine DailyMed. Label: Cosentyx—secukinumab injection.

  7. Keeling S, Wolbink GJ. Measuring multiple etanercept levels in the breast milk of a nursing mother with rheumatoid arthritis. J Rheumatol. 2010;37:1551. doi:10.3899/jrheum.100077

  8. Genentech. Herceptin prescribing information.

  9. AbbVie Inc. Humira prescribing information.

  10. Drugs and Lactation Database (LactMed). Insulin.

  11. Drugs and Lactation Database (LactMed). Ranibizumab.

  12. U.S. National Library of Medicine DailyMed. Label: Lucentis—ranibizumab injection, solution.

  13. Drugs and Lactation Database (LactMed). Filgrastim.

  14. Drugs and Lactation Database (LactMed). Infliximab.

  15. Genetech. Rituxan prescribing information.

  16. Drugs and Lactation Database (LactMed). Rituximab.

Additional Reading

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.