Breastfeeding on IBD Medication: What the Evidence Says Is Safe

Many new mothers with inflammatory bowel disease (IBD) face a difficult question after their baby arrives: is it safe to breastfeed while continuing the medication that keeps their disease under control? For most IBD treatments, current evidence suggests breastfeeding can continue safely alongside medication, with only a few exceptions requiring extra caution.

What is meant by “breastfeeding on IBD medication”?

This refers to continuing prescribed treatments for Crohn’s disease or ulcerative colitis while breastfeeding. The central question for each drug is how much passes into breast milk, and whether that amount could affect the baby. Some medications transfer into milk in very small, clinically insignificant quantities. Others are large molecules poorly absorbed by the infant’s gut, so even trace amounts are unlikely to reach the baby’s bloodstream.

Why this matters for gut inflammation

Stopping or reducing IBD medication after childbirth carries a real risk: disease flares are common postpartum, partly due to hormonal shifts and the physical stress of delivery. A flare affects the mother’s recovery and can disrupt breastfeeding itself through fatigue, pain, or the need for more aggressive treatment later. Keeping inflammation controlled with medication considered compatible with breastfeeding generally supports both maternal health and the ability to breastfeed for as long as the mother chooses.

Key mechanisms and medication classes

Biologic therapies (anti-TNF agents)

Anti-TNF drugs, such as infliximab and adalimumab, are large antibody molecules that transfer into breast milk in only minimal amounts, and what little is present is largely broken down in the infant’s gut rather than absorbed intact. Multiple observational studies and registry data have found no increased rate of infections or developmental concerns in breastfed infants of mothers on these therapies.

Vedolizumab and ustekinumab

These newer biologics block specific immune signalling pathways involved in gut inflammation, rather than suppressing the immune system broadly. Like anti-TNF agents, they are large molecules with limited transfer into milk. Available data, though smaller in volume, has not shown safety concerns in breastfed infants.

Thiopurines (azathioprine and mercaptopurine)

Thiopurines dampen the activity of immune cells driving the disease process. Studies measuring drug levels in breast milk have found only very low, often undetectable, concentrations of active metabolites. Long-term follow-up of exposed infants has not identified increased infection rates or abnormal blood counts, although some clinicians recommend routine monitoring as a precaution.

Aminosalicylates (mesalazine and sulfasalazine)

These drugs act directly on the gut lining to reduce local immune activity and are generally considered compatible with breastfeeding. A rare exception is watery diarrhoea in the infant, occasionally reported with sulfasalazine, which usually resolves if the medication is changed or stopped.

Corticosteroids

Steroids such as prednisolone pass into breast milk in small, dose-dependent amounts. At lower to moderate doses, they are considered compatible with breastfeeding. At higher doses, some specialists suggest waiting a few hours after taking the dose before feeding, though this is not always necessary.

Small molecule drugs (JAK inhibitors)

Newer oral treatments such as tofacitinib work differently to biologics: being smaller molecules, they may transfer into breast milk more readily. Evidence in breastfeeding is still limited, making individual specialist advice particularly important here.

What this does not mean

None of this should be used to start, stop, or adjust medication without discussing it with a gastroenterologist or IBD team first. Every pregnancy and postpartum period differs, and factors such as disease activity, medication combinations, and infant health all affect the balance of risks and benefits. Symptoms such as tiredness, mild abdominal discomfort, or changed bowel habits after birth do not automatically mean inflammation has returned; these can reflect normal postpartum recovery, sleep disruption, or dietary changes rather than disease activity.

Practical takeaways

• Discuss breastfeeding plans with the IBD team before delivery, ideally during pregnancy.
• Do not stop or reduce medication without medical guidance.
• Ask specifically about the medication combination used, since safety data can differ between single drugs and combined regimens.
• Report unusual infant symptoms, such as persistent diarrhoea or signs of infection, to a healthcare provider promptly.
• Keep regular postpartum follow-up appointments, as this is a higher-risk time for flares.
• Remember that maintaining disease control often supports, rather than threatens, successful breastfeeding.

Conclusion

For most IBD medications, current evidence supports continuing breastfeeding without pausing or changing treatment. Biologic therapies and aminosalicylates have the most reassuring safety data, while a few drugs, particularly newer small molecule treatments, need more individualised discussion. Long-term stability of the underlying disease remains a central goal, since uncontrolled inflammation carries its own risks to mother and infant. Decisions should always be made jointly with a gastroenterologist and, where relevant, a paediatrician, taking into account the specific regimen and the mother’s overall health.

References

1. Mahadevan U, Robinson C, Bernasko N, et al. Inflammatory bowel disease in pregnancy clinical care pathway: a report from the American Gastroenterological Association IBD Parenthood Project Working Group. Gastroenterology. 2019;156(5):1508-1524. doi:10.1053/j.gastro.2018.12.022.
2. Matro R, Martin CF, Wolf D, et al. Exposure concentrations of infants breastfed by women receiving biologic therapies for inflammatory bowel disease and effects of breastfeeding on infections and development. Gastroenterology. 2018;155(3):696-704. doi:10.1053/j.gastro.2018.05.040.
3. Julsgaard M, Christensen LA, Gibson PR, et al. Concentrations of adalimumab and infliximab in mothers and newborns, and effects on infection. Gastroenterology. 2016;151(1):110-119. doi:10.1053/j.gastro.2016.04.002.
4. Angelberger S, Reinisch W, Messerschmidt A, et al. Long-term follow-up of babies exposed to azathioprine in utero and via breastfeeding. J Crohns Colitis. 2011;5(2):95-100. doi:10.1016/j.crohns.2010.10.005.
5. Christensen LA, Dahlerup JF, Nielsen MJ, et al. Azathioprine treatment during lactation. Aliment Pharmacol Ther. 2008;28(10):1209-1213. doi:10.1111/j.1365-2036.2008.03843.x.
6. Beaulieu DB, Ananthakrishnan AN, Issa M, et al. Use of biologic therapy by pregnant women with inflammatory bowel disease does not affect infant response to vaccines. Clin Gastroenterol Hepatol. 2018;16(1):99-105. doi:10.1016/j.cgh.2017.08.041.
7. Klenske E, Osaba L, Nagore D, et al. Drug levels in the breast milk of nursing mothers with inflammatory bowel disease on vedolizumab therapy. J Crohns Colitis. 2019;13(2):267-269. doi:10.1093/ecco-jcc/jjy153.
8. Nielsen OH, Maxwell C, Hendel J. IBD medicines and safety during pregnancy and breastfeeding. Nat Rev Gastroenterol Hepatol. 2014;11(2):116-127. doi:10.1038/nrgastro.2013.135.

This article is intended for informational and educational purposes only. It does not constitute medical advice and should not be used as a substitute for professional medical guidance, diagnosis, or treatment.

More from Gastro Living