Special situations
For people living with ulcerative colitis (UC), deciding to start a family brings a wave of questions that healthy peers rarely have to consider. Which medications are safe? Will a flare during pregnancy harm the baby? What about delivery with a J-pouch? The reassuring headline from decades of research, reinforced by the first global pregnancy and IBD guidelines published in August 2025, is that most people with UC can have healthy pregnancies. The path forward depends on planning, disease control, and informed medication decisions.
Why Remission Before Conception Matters
The single strongest predictor of a smooth pregnancy is disease status at the time of conception. When UC is in remission, roughly 85% of pregnancies proceed without complications, and the risk of flare during pregnancy, around 26 to 35%, is comparable to the baseline flare risk in non-pregnant patients. When disease is active at conception, the picture changes dramatically: about half of those patients will see symptoms worsen throughout pregnancy.
The American Gastroenterological Association recommends achieving three to six months of steroid-free remission before trying to conceive. That window allows time to confirm disease stability and minimize the chance of a pregnancy-related flare. For both partners, this pre-conception period is the time to review every medication with a gastroenterologist and, if relevant, a maternal-fetal medicine specialist.
Medication Safety: What Stays, What Goes
The 2025 global consensus guidelines are clear on one foundational point: continuing effective therapy is safer than stopping it. Uncontrolled inflammation poses a greater risk to pregnancy than nearly all UC medications.
Medications generally considered safe during pregnancy:
Mesalamine (5-ASA) formulations remain a cornerstone of UC treatment and carry a well-established safety profile during pregnancy and breastfeeding
Biologics, including anti-TNF agents, vedolizumab, and ustekinumab, have been studied extensively; a meta-analysis of 48 studies and nearly 7,000 patients found pregnancy outcomes comparable to the general population
Thiopurines such as azathioprine can be continued, though dose adjustments may be needed
Medications to avoid or use with caution:
Methotrexate is strictly contraindicated during pregnancy and must be stopped well before conception
JAK inhibitors (tofacitinib, upadacitinib) and S1P receptor modulators (ozanimod) have shown embryotoxicity in animal studies and should be switched to safer alternatives before conception
Corticosteroids can be used short-term for flare management but are not ideal for long-term use during pregnancy
Sulfasalazine and Male Fertility
Male partners on sulfasalazine should be aware that the medication causes reduced sperm count, decreased motility, and increased abnormal sperm morphology. The effect is caused by the sulphapyridine component of the drug, not the active 5-ASA portion. The good news: these changes are fully reversible. Studies show pregnancies occurring at a median of 2.5 months after stopping sulfasalazine. Switching to an alternative mesalamine formulation eliminates the fertility impact while maintaining UC control.
Managing a Flare During Pregnancy
Despite careful planning, flares can happen. When they do, the priority is to control inflammation quickly. Untreated active disease carries a higher risk of preterm delivery and low birth weight than the medications used to treat it. Gastroenterologists typically use mesalamine for mild flares and short courses of corticosteroids for moderate-to-severe episodes. Biologic therapy can be initiated or continued safely throughout pregnancy when disease demands it.
Pregnancy with a J-Pouch
Patients who have undergone ileal pouch-anal anastomosis (IPAA) can carry pregnancies safely. Research on 283 pregnancies after IPAA found complication rates of about 12.7%, with most issues being manageable, including occasional small bowel obstruction and pouchitis. Pouch function changes are common during the third trimester, with increased stool frequency and occasional urgency, but function typically returns to baseline after delivery.
The question of vaginal delivery versus cesarean section in J-pouch patients has been studied extensively. Current evidence shows that stool frequency and continence are not significantly affected by delivery method, meaning the decision can be guided by obstetric considerations rather than pouch concerns alone. That said, this is a conversation to have with both your surgeon and obstetrician early in pregnancy.
Breastfeeding and the Postpartum Period
The postpartum period deserves as much attention as pregnancy itself. Roughly one in three women with IBD experience a flare in the first year after delivery, with therapy de-escalation being a key risk factor. Breastfeeding itself does not increase flare risk.
Most UC medications are compatible with breastfeeding. Mesalamine, thiopurines, and biologics all appear in breast milk at very low levels and have not been linked to adverse infant outcomes. Methotrexate and JAK inhibitors remain off-limits during nursing. The 2025 global guidelines recommend continuing all biologics throughout lactation.
The most important postpartum decision is to stay on the medications that kept you in remission during pregnancy. Stopping therapy after delivery, whether because of breastfeeding concerns or a sense that the "risky period" has passed, is one of the most common triggers for postpartum flares.