Crohn's Disease and Breastfeeding: What to Know

Yes, most people with Crohn's disease can breastfeed, and the 2025 global consensus on pregnancy and IBD recommends it (Mahadevan 2025). What makes Crohn's different from colitis is not the milk. It is the extra things Crohn's brings into the postpartum months: antibiotics for perianal disease, methotrexate and upadacitinib, a shortened ileum and its B12, surgery with a newborn at home, and a widely quoted study that seemed to show breastfeeding made Crohn's flare.

That last one deserves to be untangled first, because it has shaped advice for twenty years.

What this page covers, and what it hands off

The general breastfeeding questions are the same in Crohn's and colitis, so we answer them once. Our post on breastfeeding with ulcerative colitis walks through how biologics get into milk, the drug-by-drug table for 5-ASAs, steroids, thiopurines, anti-TNFs, vedolizumab and ustekinumab, the live-vaccine disagreement, colonoscopy and bowel prep while nursing, and combination feeding. Nearly all of that applies to Crohn's unchanged.

This page spends its words on what only Crohn's raises. If you are earlier in the journey, our posts on whether it is safe to get pregnant with Crohn's (which includes the perianal delivery evidence) and whether Crohn's affects fertility come first.

Nothing here is a recommendation to start, stop or change a medicine. The point is to know which questions to ask, and where the published sources disagree.

Does breastfeeding make Crohn's flare? The 3.8 that keeps getting quoted

No study has shown that breastfeeding itself makes Crohn's flare. The number people find, and some clinicians remember, comes from a 2005 US study of 122 women with IBD who had given birth in the previous five years (Kane 2005).

Here is what that abstract actually reports:

• Only 44% (54 of 122) breastfed. Reasons included physician recommendation and fear of medication interactions.
• 43% of those who breastfed (23 of 54) had a postpartum flare.
• Unadjusted, breastfeeding looked linked to flares, with an odds ratio of 2.2.
• Split by disease, the association sat entirely in Crohn's, with an odds ratio of 3.8 (95% CI 1.9 to 7.4). In colitis it was 0.89, which is no association.
• When adjusted for medication cessation, the odds ratio became non-significant. The authors concluded that any relationship "may be more a consequence of discontinuation of IBD therapies."

The 2025 consensus fills in the step the abstract leaves out: 74% of the women who breastfed in that study (40 of 54) had stopped their IBD medicines before they started breastfeeding, and that group carried the extra flare risk (Mahadevan 2025). The abstract does not say whether the Crohn's-only figure was adjusted separately, so we cannot tell you what the 3.8 becomes on its own. What we can say is that the headline number describes women who came off treatment, not a property of breastfeeding.

The next study went the other way. A Canadian population-based survey found women with Crohn's started breastfeeding as often as the general population (81.9% vs 77.1%), and postpartum flares were 26% in Crohn's women who breastfed against 29.4% in those who did not (Moffatt 2009). That difference was not significant. The consensus counts four retrospective cohorts with 543 women, 76% of whom breastfed, and cites a meta-analysis that found no effect of breastfeeding on postpartum disease activity (odds ratio 0.89, 95% CI 0.35 to 2.29), with high heterogeneity between studies (Mahadevan 2025).

So why does the 3.8 survive? Partly because it is a striking number in a title-friendly direction, and partly because it is true as a description: in that clinic, in that era, women with Crohn's who breastfed did flare more. They were also the women who had been told to stop their medicines to do it.

The postpartum months in Crohn's specifically

Crohn's does not seem to flare more after birth than it would anyway, but stopping or cutting back treatment does raise the risk. That is the pattern across the studies that separate the two diseases.

A prospective European study followed 92 pregnant women with Crohn's through pregnancy and six months after delivery, matched to non-pregnant women with Crohn's. There was no significant difference in disease course during pregnancy or postpartum. Pregnant women with colitis, by contrast, did relapse more (Pedersen 2013). That split is one reason this page exists separately from the colitis one.

A US study of 206 women at two referral centres (97 with Crohn's) found 31.6% flared within a year of delivery (Yu 2020). Flares were not related to disease type or mode of birth. They were predicted by:

• disease activity in the third trimester (odds ratio 6.27)
• therapy de-escalated during pregnancy (odds ratio 3.00)
• therapy de-escalated after delivery (odds ratio 4.43, 95% CI 1.55 to 12.65)

One arithmetic flag: the third-trimester odds ratio is printed as 6.27 with an interval of 2.81 to 17.27, whose log-scale midpoint is about 6.97. The other two intervals check out. We cannot tell from the abstract whether 6.27 or the interval is the slip; either way, active disease late in pregnancy was the strongest predictor.

The consensus summarises a meta-analysis in which stopping a biologic in the third trimester raised the odds of postpartum disease activity (odds ratio 1.77, 95% CI 1.01 to 3.10), and it is candid that the women who stopped were not a random group, which muddies the comparison (Mahadevan 2025). Its bottom line on breastfeeding is blunt: IBD medicines "should not be stopped in the postpartum period."

What about weaning? In Crohn's threads, a recurring story is a flare that arrives when the baby stops nursing, sometimes passed on as a gastroenterologist's warning to wean gradually (r/CrohnsDisease). Others describe the reverse, a calm year of breastfeeding with no medication at all. We could not find a study that measured flares around weaning, so treat it as an untested idea rather than a rule. If you notice it, log it; it is exactly the kind of personal pattern that is worth showing your team.

Crohn's medicines the colitis page does not cover

Several drugs used mostly or only in Crohn's have their own breastfeeding evidence, and for two of them the sources disagree. Here is the short version, with the reasoning below.

Certolizumab

Certolizumab is an antibody fragment without the Fc portion, and the consensus describes antibody transfer into milk as Fc-receptor mediated. In CRADLE, 17 mothers on certolizumab gave 137 milk samples; 56% had no measurable drug, and the median relative infant dose was 0.15% (Clowse 2017). Its authors also cite the Fc-free structure as a reason the baby is unlikely to absorb what does get through. The abstract itself describes CRADLE as industry-sponsored, and certolizumab is the sponsor's product, so weigh it with that in mind. The independent PIANO registry also found certolizumab in the milk of only 3 of 13 treated women, at low levels (Matro 2018).

LactMed adds one thing worth knowing if your supply is struggling: an analysis of US spontaneous adverse-event reports raised a possible signal for lactation insufficiency with anti-TNF drugs, and TNF has a role in milk production (LactMed: certolizumab). Spontaneous reports cannot show cause, so this is a reason to ask for lactation support early, not a reason to doubt the drug.

Risankizumab, guselkumab and mirikizumab

These IL-23 drugs are now common in Crohn's, and none has human breastfeeding data. The consensus still lists them as compatible, reasoning that monoclonal antibodies pass into milk poorly, that roughly half of the antibody in a baby's gut is digested, and that very little of the rest is absorbed (Mahadevan 2025). LactMed reaches a similar view for risankizumab on the same molecular-size grounds (LactMed: risankizumab). In plain terms: reassuring theory, no measured data yet. Two recent r/CrohnsDisease thread titles refer to a lactation study recruiting mothers on guselkumab (r/CrohnsDisease), which suggests that gap is being worked on.

Upadacitinib: the one where newer data arrived

The consensus says mothers on JAK inhibitors, including upadacitinib, should not breastfeed, and at the time it was written it said nobody knew whether upadacitinib reached human milk (Mahadevan 2025). That has since changed. LactMed now summarises a 2026 report of four women with IBD taking upadacitinib: daily relative infant doses ranged from 3.8% to 9.6%, a quarter of the 40 single samples came out above about 10.6%, and the authors could not explain the wide spread (LactMed: upadacitinib). Those figures sit around the 10% line conventionally treated as low risk, higher than any other drug in this table. The report's Europe PMC record lists the drug's manufacturer among its funders. The manufacturer recommends not breastfeeding for 6 days after the last dose.

None of that loosens the consensus position. It does mean that if you see "nobody knows if it gets into milk" on an older page, that is now out of date.

Methotrexate: three sources, three positions

Methotrexate is used far more in Crohn's than in colitis, and this is where you are most likely to hear conflicting advice.

• The 2025 IBD consensus notes the relative infant dose is low (0.11%) but that an active metabolite is detectable in milk, and concludes breastfeeding "should be avoided" on methotrexate. If a low weekly dose is used, there is no compatible alternative and the mother strongly wants to breastfeed, it "may be considered with close monitoring of the infant" (Mahadevan 2025).
• LactMed says recent guidelines treat low single or weekly doses, such as those used in rheumatoid arthritis, as an acceptable alternative during breastfeeding, while older expert opinion warns against it (LactMed: methotrexate).
• The 2024 European rheumatology recommendations do not include methotrexate in the abstract's list of lactation-compatible drugs, though they list it as compatible for men (Rüegg 2025).

In practice, 68% of 856 gastroenterologists surveyed in 2025 said they advise against methotrexate during breastfeeding (Casanova 2025). If methotrexate is part of your plan, ask about it by name, and ask what the alternative would be.

Perianal Crohn's after birth: antibiotics, scans and sitting to feed

Perianal disease is the most Crohn's-specific part of the postpartum months, and it brings its own breastfeeding decisions. A US centre that followed 190 women with IBD through 322 deliveries found 10% had a postpartum perianal flare (Otero-Piñeiro 2024). The strongest predictors were active perianal disease at delivery (odds ratio 96) and any previous perianal disease (odds ratio 22). Caesarean section did not protect against them. Which birth route makes sense is covered in our Crohn's pregnancy post; here the question is what happens if perianal disease flares while you are nursing.

Metronidazole and ciprofloxacin

These are the two antibiotics most often used in IBD, and the consensus treats them differently (Mahadevan 2025):

• Metronidazole and its metabolite reach milk in amounts the consensus calls relatively high, about a tenth of a therapeutic infant dose. It reports diarrhoea and more Candida growth in exposed babies, notes the unknown effects on the baby's microbiome and immune system, and says "we generally advise against breastfeeding for mothers taking metronidazole." If a short oral course, around a week, is necessary, it recommends watching the baby closely for diarrhoea or thrush. LactMed describes expert opinion on longer courses as divided (LactMed: metronidazole).
• Ciprofloxacin appears in milk at low levels, and the consensus calls it low risk in nursing mothers, again with monitoring for diarrhoea or thrush (LactMed: ciprofloxacin).

Here is the gap that matters: in the 2025 survey, only 27% of gastroenterologists advised against metronidazole during breastfeeding (Casanova 2025). The same survey found only 36% had consulted obstetric colleagues on breastfeeding safety and 13% believed every IBD drug was safe while nursing. So you may well be prescribed metronidazole for an abscess with no comment about feeding. That is a moment to ask whether an alternative would work, and if not, what to watch for in the baby.

Scans and examinations

A pelvic MRI is the usual way to map perianal disease, and it often involves gadolinium contrast. The consensus states that, in line with international radiology guidance, breastfeeding does not need to be interrupted after iodinated or gadolinium contrast; if you want to avoid any exposure, a 24-hour pause is "more than adequate" (Mahadevan 2025). The same document says that after sedation with midazolam, fentanyl or propofol, breastfeeding can resume once you are alert enough to feed, with a more cautious gap suggested for midazolam with a newborn.

Sitting to feed

Nobody has studied feeding positions in perianal Crohn's, but the threads are full of practical workarounds: feeding side-lying in bed, using a ring cushion, or having someone hand the baby over so you are not getting up and down. One mother with Crohn's described feeding on the toilet during a bout of diarrhoea, and a toddler who now asks about it every time she goes (r/CrohnsDisease). It is mundane, and it is the kind of thing that decides whether breastfeeding lasts.

Surgery, scopes and painkillers while nursing

Crohn's surgery with a young baby is more common than people expect, and breastfeeding can usually continue through it. The UK Association of Anaesthetists' guideline says breastfeeding is acceptable after anaesthesia and should be supported as soon as the woman is alert and able to feed, without discarding milk (Mitchell 2020). It also asks hospitals to plan for breastfeeding during the stay.

A Crohn's thread about an ileal resection with a three-month-old shows how the practical side plays out (r/CrohnsDisease). The surgeon said breastfeeding was fine; the hospital offered a single room. Commenters who had been through the same surgery were blunt that the first nights, with a nasogastric tube and heavy pain relief, left no capacity to care for a baby, and that another adult needed to be there at all times for the baby's safety. One mother hospitalised for a partial obstruction asked for the lactation team to go through every inpatient and discharge medicine with her, and kept breastfeeding.

Painkillers are the medicines to ask about by name. LactMed notes that maternal use of any oral opioid at high doses can make a breastfed baby drowsy, that newborns are particularly sensitive, and that increased sleepiness, difficulty feeding, breathing problems or limpness in the baby need a doctor straight away (LactMed: codeine).

Anti-inflammatory painkillers raise a separate, Crohn's-specific question. In a US cohort of 791 people with IBD in remission, regular NSAID use (five or more times a month) was linked to active Crohn's six months later (23% vs 15%), but not to active colitis (Long 2016). The authors say regular NSAID use may increase Crohn's activity, or may simply mark a less robust remission. Regular paracetamol (acetaminophen) use was linked to active Crohn's too, which to our reading fits the second explanation at least as well as the first. A Crohn's thread about caesarean recovery shows the full range: some mothers avoided ibuprofen, some took it for a few days after clearing it with their IBD team (r/CrohnsDisease). That is the right instinct: ask, rather than default either way.

Feeding a baby from a gut that absorbs less

After ileal resection, B12 is the nutrient to ask about, because the baby's supply depends on yours. B12 is absorbed in the last part of the small intestine, which is exactly where Crohn's surgery often happens.

A systematic review of 42 studies found that Crohn's disease without resection did not raise the risk of B12 deficiency, but ileal resections longer than 30 cm did, resections shorter than 20 cm did not, and 20 to 30 cm gave inconsistent results (Battat 2014). A follow-up pilot study found true deficiency was rare once a confirmatory blood marker was used, and warned that a low B12 result alone can over-diagnose it (Battat 2017).

Why it matters for breastfeeding: infant B12 depends on the mother's levels, through the baby's stores at birth and the amount in breast milk, and formula is supplemented with it (Roumeliotis 2012). When infants do become deficient, signs usually appear between 2 and 12 months: poor feeding, weight loss, irritability, and in severe cases lethargy and loss of skills they had gained. Most features improve quickly with treatment, though the authors note long-term outcomes are less certain. The cases in that report came from a vegan diet and from pernicious anaemia; we found no published case tied specifically to a mother's Crohn's resection. The mechanism is the same, though, which is why it is worth a question rather than a worry.

Other practical points from threads and the evidence:

• Weight. Several mothers with Crohn's describe losing weight while breastfeeding despite eating constantly, or choosing formula for a second baby because they could not eat enough during a flare. Our guide to gaining weight with Crohn's covers the nutrition side; tell your team if you are losing weight you cannot explain.
• Milk supply during a flare. Experiences split. One mother with Crohn's said her supply fell from plenty to nothing within two weeks of a flare at three months postpartum (r/CrohnsDisease); others flared throughout and saw no drop. We found no study measuring milk supply in Crohn's flares. The consensus notes that milk from mothers with IBD has shown differences in immune proteins and fat content, with unclear long-term meaning (Mahadevan 2025).
• Bowel rest or liquid diets. A mother asked whether she could rest her bowel while breastfeeding; the replies, rightly, said to talk to her doctors first (r/CrohnsDisease). We found no study of exclusive liquid nutrition during lactation. Cutting intake while making milk carries its own nutritional risk, so this is a dietitian-and-IBD-team decision.

Will breastfeeding protect my baby from Crohn's?

Maybe a little, but the studies conflict, and it is not something to carry guilt about. A 2017 meta-analysis of 35 studies found that ever being breastfed was associated with lower odds of Crohn's (odds ratio 0.71), more strongly in Asian populations (0.31) and with at least 12 months of breastfeeding (0.20) (Xu 2017). Those are mostly case-control studies, which depend on recalled infant feeding decades later.

A 2024 analysis of three prospective birth cohorts with nearly 170,000 children found no association between breastfeeding duration and later IBD, including for Crohn's separately (Agrawal 2024). The consensus adds that most of the protective data come from mothers without IBD, and one French study even found breastfeeding linked to higher odds of paediatric Crohn's (Mahadevan 2025).

When a meta-analysis was posted to r/CrohnsDisease, the replies were a long list of people breastfed for two years who developed Crohn's anyway, and parents who had nursed children later diagnosed (r/CrohnsDisease). Several pointed out, correctly, that a correlation in observational data is not a promise. The fuller discussion, including family risk, is in the colitis breastfeeding post.

"Can breast milk help Crohn's disease?" We decline to endorse this

We found no human trial showing that adults with Crohn's benefit from drinking breast milk. The search suggestion exists, so it is worth answering directly.

The science behind the idea is real but early and almost entirely in animals: the consensus mentions that breast milk limited colitis in genetically modified mice and that milk exosomes prevented intestinal inflammation in a mouse model (Mahadevan 2025). A mouse model is not a treatment.

The risks, on the other hand, are measured. When US researchers bought 101 samples of breast milk online, 74% were colonised with Gram-negative bacteria or had high total bacterial counts, and 21% contained cytomegalovirus DNA (Keim 2013). For an adult taking immunosuppressants, that is a poor trade for an unproven benefit. If you are curious about the biology, ask your IBD team about trials; do not substitute it for treatment.

Who actually coordinates this?

Usually nobody, unless you make it happen. The 2025 survey found few gastroenterologists had referral routes to IBD-specialised obstetricians or paediatricians (Casanova 2025). In practice, the people involved are:

• Your IBD team for whether to continue, change or restart each Crohn's medicine.
• A pharmacist for drug-in-milk questions, especially new prescriptions from other teams such as surgeons, dentists or emergency departments. In the UK, health professionals can contact the NHS Specialist Pharmacy Service's breastfeeding medicines advice service (SPS). LactMed is free for anyone.
• A lactation consultant or midwife for latch, supply and positions.
• The baby's doctor or health visitor, who needs your medicine list, because it affects vaccine timing for some drugs. The live-vaccine debate is covered in the colitis breastfeeding post.

Bring one written list to each of them: every medicine, its dose schedule, and when you last had it.

A worked example: one abscess, two conversations

Picture someone eight weeks postpartum, exclusively breastfeeding, on an anti-TNF that she continued through pregnancy. She develops a painful lump near the anus and a low fever.

The rushed version. She goes to urgent care, is told it is probably an abscess, and leaves with a metronidazole prescription. Nobody asks about feeding. She finds a forum saying metronidazole is "fine", another saying to stop breastfeeding, and pumps and discards milk for two days while her supply drops.

The prepared version. She tells the clinician up front that she has perianal Crohn's and is exclusively breastfeeding. She asks three things: does this need drainage today; is there an antibiotic option the consensus considers lower risk while nursing; and if metronidazole is still the best choice, what should she watch for in the baby? She calls her IBD team the same day, because a perianal abscess on biologic treatment is something they want to know about, and they may arrange a pelvic MRI. She keeps her anti-TNF on schedule unless they tell her otherwise.

The second version does not need medical knowledge. It needs the right questions written down before the bad day.

What to track in the first postpartum year

A short daily log is worth more than a perfect memory at your next appointment. Sleep deprivation erases detail, and postpartum flares are easy to mistake for ordinary new-parent exhaustion. Our guide on what to track in an IBD symptom diary gives the full structure; for this period, add:

• Stool count and pain, scored the same way each day. The Harvey-Bradshaw Index is the score many Crohn's clinics use.
• Medicine dates, including any missed doses around birth and the date each drug was restarted.
• Perianal changes: new pain, swelling, discharge or a lump, with dates.
• Feeding notes: supply changes, mastitis, and any diarrhoea, thrush or unusual sleepiness in the baby after a new medicine.
• Weight, every week or two.
• Weaning steps, if you want to test the weaning-flare idea on yourself.

Clairop is built for exactly this kind of log: it can turn daily entries into a one-page report showing your score trend, bowel pattern, overnight episodes and medication adherence for your IBD team. You can see how that works on how it works. If you are mid-flare and need to log fast, our post on tracking symptoms during a flare covers the shortcuts.

When to see a doctor promptly

Contact your IBD team or seek care promptly if, while breastfeeding, you have:

• Fever, a painful lump near the anus, or new discharge (possible abscess)
• Gas or stool from the vagina (possible rectovaginal fistula)
• Blood in your stool, or more than your usual
• Severe abdominal pain with vomiting and no stool or wind (possible blockage, needs same-day assessment)
• Unexplained weight loss, or signs of anaemia such as breathlessness and marked tiredness
• Symptoms waking you at night, beyond waking for feeds
• A flare after stopping or cutting back a medicine

And for the baby: increased sleepiness, poor feeding, breathing difficulty or floppiness after you start a new medicine needs a doctor immediately. Our guide on how to tell if you are in a Crohn's flare helps sort flares from look-alikes, and Crohn's night sweats covers fever on biologics.

Myths about Crohn's and breastfeeding

"Breastfeeding makes Crohn's flare." The study behind this found the link disappeared once women stopping their medicines were accounted for (Kane 2005), and later studies found no increase.

"You have to choose between your medicine and breastfeeding." For most Crohn's treatments, including anti-TNFs, vedolizumab, ustekinumab and the IL-23 drugs, the 2025 consensus says you may breastfeed. The exceptions are JAK inhibitors and S1P modulators, with methotrexate and metronidazole as contested cases.

"Any antibiotic means pumping and dumping." Ciprofloxacin is described as low risk. Metronidazole is the one the consensus is cautious about, and even then a monitored short course is an option.

"Breastfeeding guarantees my baby will not get Crohn's." The best prospective data found no link with duration (Agrawal 2024).

"Breast milk can treat adult Crohn's." The supporting work is in mice, and milk bought online carries measured infection risks (Keim 2013).

The honest bottom line

You can breastfeed with Crohn's disease on most of the treatments used for it today, and the newest global consensus recommends it. The flare risk people worry about traces back to stopping medicines, not to breastfeeding. What Crohn's adds is a handful of specific decisions: metronidazole for perianal disease, methotrexate, upadacitinib, surgery and painkillers with a baby at home, and B12 after ileal resection. None of them needs to be solved alone. Write the questions down, bring your medicine list to everyone involved, and if you decide formula or combination feeding is right for you, that is a legitimate decision too.