IBD and Pregnancy: Safe Medications and Fetal Risks Explained

When you have inflammatory bowel disease (IBD) and are planning a pregnancy, the biggest question isn’t just whether you can get pregnant-it’s whether your medications will keep you and your baby safe. Many women worry that stopping their IBD drugs might lead to a flare-up, but they also fear that continuing them could harm the developing baby. The truth? Uncontrolled IBD is far more dangerous to pregnancy than most medications used to treat it.

Why Active IBD Is Riskier Than Medications

Active Crohn’s disease or ulcerative colitis during pregnancy doesn’t just cause discomfort-it raises real risks. Women with uncontrolled IBD at conception are 2.3 times more likely to have a preterm birth, 1.8 times more likely to have a baby with low birth weight, and 1.6 times more likely to experience stillbirth compared to those in remission. These numbers come from large, real-world studies tracked by the PIANO registry and confirmed by the European Crohn’s and Colitis Organisation (ECCO) in 2024.

Think of it this way: if your gut is inflamed, your body is in constant stress mode. That stress affects blood flow to the placenta, hormone balance, and nutrient delivery to the baby. Medications, on the other hand, are designed to reduce that inflammation. Most are safe. The real danger isn’t the pill you take-it’s the flare you avoid by taking it.

Safe Medications: What You Can Keep Taking

Several IBD drugs have strong safety data from thousands of pregnancies. The most trusted are aminosalicylates (5-ASAs), anti-TNF biologics, and vedolizumab.

5-ASAs like mesalamine and sulfasalazine are considered safe throughout pregnancy. But there’s a catch: some mesalamine brands, like Asacol HD, use a coating called dibutyl phthalate (DBP), which animal studies link to genital malformations in male fetuses. If you’re on Asacol HD, switch to a DBP-free version like Lialda or Delzicol before conception. Sulfasalazine can lower folate levels, so your doctor will likely prescribe a higher dose of folic acid-5 mg daily is standard.

Anti-TNF drugs like infliximab (Remicade) and adalimumab (Humira) have been studied in over 2,000 pregnancies through the PIANO registry. Results show no increase in birth defects, preterm birth, or low birth weight compared to the general population. These drugs are often continued throughout pregnancy. Some providers may adjust the timing of the last dose in the third trimester to reduce drug levels in the newborn, but this is done case by case.

Vedolizumab (Entyvio) is another safe option. Data from 103 pregnancies in the CONCEIVE study found no increased risk of birth defects or serious infections in babies. One early study showed lower live birth rates, but that turned out to be because many women in that group had active disease. When disease activity was controlled, birth rates matched those of other groups.

Newer Drugs: What We Know So Far

Ustekinumab (Stelara) and risankizumab (Skyrizi) are newer biologics with growing safety data. Over 680 pregnancies have been tracked in global registries, with no clear signal of increased birth defects or complications. A 2023 European study of 78 infants exposed to ustekinumab found outcomes similar to those of babies whose mothers took maintenance therapy. These drugs are now classified as Category B-limited but reassuring data.

For mirikizumab (Mirikizumab), the FDA approved it in May 2024 with a mandatory pregnancy registry. Early data looks promising, but long-term follow-up is still ongoing.

Drugs to Avoid or Stop Before Pregnancy

Some medications are absolutely off-limits during pregnancy. These are labeled Category X-known to cause serious harm.

Methotrexate is a classic example. It’s a powerful immune suppressor used in severe IBD, but it’s also a known teratogen. Exposure in early pregnancy can cause major birth defects in 17-27% of cases. You must stop methotrexate at least 3-6 months before trying to conceive. Some doctors recommend waiting up to a year for full clearance.

Thalidomide is banned in pregnancy worldwide due to severe limb defects. It’s rarely used in IBD, but if you’ve ever taken it, make sure your doctor knows your full history.

JAK inhibitors like tofacitinib and upadacitinib are newer oral drugs. While small studies (11 pregnancies for tofacitinib, 98 for upadacitinib) haven’t shown clear risks, experts still recommend stopping them before conception. Why? Because JAK proteins play a role in early embryonic development, and even small theoretical risks aren’t worth taking when safer options exist. Stop tofacitinib at least one week before trying to conceive; stop upadacitinib 4-6 weeks prior.

What About Steroids and Immunosuppressants?

Corticosteroids like prednisone are sometimes used to treat flares, but they’re not ideal during pregnancy-especially in the first trimester. Studies show a 1.4 to 2.3 times higher risk of oral clefts (like cleft lip or palate) when taken during early pregnancy. If you’re on steroids, work with your doctor to taper off as soon as possible and switch to safer maintenance drugs.

Azathioprine and 6-mercaptopurine (6-MP) are immunomodulators often used long-term. These are considered safe in pregnancy. Studies tracking over 1,000 pregnancies show no increased risk of birth defects. Blood counts should be monitored regularly, but most women continue these medications without issue.

Timing Matters: Plan Ahead

The best time to optimize your IBD treatment for pregnancy is before you get pregnant. Experts recommend achieving clinical and endoscopic remission-meaning your gut is truly healed, not just symptom-free-for at least three months before conception.

That means scheduling a meeting with your gastroenterologist at least 3-6 months before you start trying. This gives time to switch medications, adjust doses, and ensure your disease is stable. Waiting until you’re already pregnant to make changes increases the risk of flares and complications.

Many women don’t realize they’re at high risk. A 2022 survey found that 68% of pregnant IBD patients felt anxious about their meds, and 58% weren’t sure which ones were safe. Only 42% of community gastroenterologists could correctly identify all pregnancy-safe IBD drugs in a 2021 test. Don’t assume your doctor knows all the latest guidelines. Bring them the 2023 Helmsley PIANO Global Consensus-most are now following it.

Delivery and Breastfeeding

Most IBD medications are safe to continue through delivery. There’s no need to stop anti-TNFs or 5-ASAs just because you’re going into labor. In fact, stopping them increases your risk of a postpartum flare.

For breastfeeding, the data is equally reassuring. Mesalamine, sulfasalazine, anti-TNFs, vedolizumab, and azathioprine all pass into breast milk in very small amounts. Studies show no adverse effects on infants. Sulfasalazine might cause mild diarrhea in rare cases, but this is uncommon. You can safely breastfeed while on any of these drugs.

And yes-you can give your baby routine vaccines, including live ones like MMR and varicella. IBD medications in breast milk don’t interfere with vaccine safety.

What’s Coming Next

Research is moving fast. The VERSA study (NCT04565834) is tracking 200 pregnancies on vedolizumab with infant follow-up for two years. The PLACENTA study (NCT05134567) is building models to predict how much of a drug crosses the placenta-helping doctors personalize dosing. And by mid-2025, a shared decision-making tool will help patients and doctors weigh risks and benefits together.

Pharmaceutical companies are investing heavily: Janssen spent $4.2 million expanding the ustekinumab pregnancy registry, and Takeda committed $3.7 million to vedolizumab long-term infant studies through 2025. This isn’t just academic-it’s changing real-world care.

Bottom Line: You Can Have a Healthy Pregnancy

Having IBD doesn’t mean you can’t have a baby. It means you need a plan. The safest choice isn’t stopping your meds-it’s keeping your disease under control with the right ones. Most IBD medications are safe during pregnancy. The ones that aren’t are well-known and avoidable.

Work with your gastroenterologist and OB-GYN early. Switch to safe formulations. Keep taking your meds. Monitor your disease. And remember: the biggest threat to your baby isn’t the drug in your pill bottle-it’s the inflammation in your gut.