Inflammatory bowel disease in pregnancy: Crohn's disease, ulcerative colitis and medicines

The NHS page on Crohn's disease says you can usually have a healthy pregnancy, but that poorly controlled symptoms can make it harder to conceive or cause problems in pregnancy, and that some Crohn's medicines are not suitable if you are pregnant. It advises speaking to a specialist before trying for a baby or as soon as you find out you are pregnant.

A review of IBD and reproductive health describes what a preconception visit should cover: reviewing and optimising medicines, confirming that disease is in remission using tests such as faecal calprotectin or colonoscopy, and checking routine matters such as vaccination status, vitamin D and iron. In a prospective study cited by the review, women who had a half-hour counselling session were more likely to keep taking their medicines and prenatal vitamins, stop smoking and have better-controlled disease in pregnancy.

Women with quiet or medically treated IBD and no previous pelvic surgery have infertility rates similar to the general population, according to the same review, whereas active inflammation, painful perianal disease and scarring from previous operations can reduce fertility. Pelvic surgery for ulcerative colitis, particularly the ileal pouch (IPAA) operation, can substantially reduce the chance of conceiving, which is why surgeons and fertility specialists discuss timing of operations for people who hope to have children.

Male fertility can be affected too: sulfasalazine and methotrexate can reduce sperm quality, usually reversibly after stopping. The British Society of Gastroenterology says men taking methotrexate may not need to stop it before conception, although evidence is limited.

Disease activity at conception shapes what follows. The review reports that of women in remission when they conceive, about 80 per cent remain in remission, while active ulcerative colitis worsens in a large share of pregnancies. A UK study of more than 364,000 pregnancies, including nearly 2,000 in women with IBD, found only a small increase in preterm birth overall, with a higher risk of low birth weight and postpartum haemorrhage in Crohn's disease.

Tell the midwife about IBD at the first booking appointment so that care can be shared between obstetric and gastroenterology teams. New bloody diarrhoea, severe abdominal pain, fever, dehydration or being unable to keep fluids down needs same-day advice from the IBD nurse line, GP or NHS 111, and 999 if you feel severely unwell. Treating a flare early is generally safer for the baby than letting it smoulder.

Reviews of IBD drug safety conclude that most medicines, with the exception of methotrexate, are safe or low-risk in pregnancy and that the risks of stopping them generally outweigh the risks of continuing. The BSG guideline adds that medicines safe in pregnancy are also safe in breastfeeding and should continue.

• Aminosalicylates (mesalazine, sulfasalazine): meta-analysis found no significant increase in malformations, stillbirth or preterm delivery; sulfasalazine reduces folate absorption, so a higher folic acid supplement is advised.

• Thiopurines (azathioprine, mercaptopurine): considered safe and usually continued; newborns of exposed mothers may need a blood count check.

• Corticosteroids: helpful for flares; some studies suggest a small rise in cleft palate risk with first-trimester exposure while others do not, and the benefit of remission is considered to outweigh the risk.

• Anti-TNF biologics (infliximab, adalimumab, certolizumab): continued in people at risk of flare; in sustained remission the last dose can sometimes be given around weeks 22 to 24 to limit drug passing to the baby.

• Vedolizumab, ustekinumab and tofacitinib: fewer data, so the lack of evidence and the consequences of stopping are discussed before conception.

• Methotrexate: stop at least six months before conception according to the BSG, and stop immediately if pregnancy occurs unexpectedly.

• Antibiotics for perianal disease or pouchitis may need switching; penicillins are first-line in pregnancy and ciprofloxacin is generally avoided.

Caesarean rates are higher in women with IBD than the general population, but only a minority reflect true obstetric reasons. A review explains that vaginal delivery carries a risk of anal sphincter or perineal damage, which can worsen perianal Crohn's disease or pouch function, so caesarean birth is recommended for active perianal disease or an ileoanal pouch. Otherwise the mode of birth is the obstetrician's and woman's decision.

People with previous perianal Crohn's disease, fistulas or an ileostomy should have the plan for birth agreed in advance with the obstetric and colorectal teams.

Anti-TNF drugs cross the placenta mostly in the third trimester, and infliximab and adalimumab can be detected in babies for several months, in some infants up to a year. For that reason the guidelines recommend delaying live vaccines in exposed infants for 6 to 12 months, guided by the paediatric team. Low levels of biologics appear in breast milk, and babies breastfed by mothers on biologics have similar infection rates and milestones to other infants.

Breastfeeding is generally compatible with aminosalicylates, thiopurines and biologics. Methotrexate and ciclosporin are not recommended, and manufacturers advise a gap after tofacitinib. The BSG notes that stopping treatment may be followed by relapse in pregnancy or after birth, so contact the IBD team if symptoms return rather than waiting for the routine review.