Women with inflammatory bowel disease may wish to stop taking their drugs during pregnancy because of the perceived risk of harm to the fetus. However, it is crucial that the disease is controlled, and fears of adverse drug events—which are not always evidence based—should be allayed. The medical management of inflammatory bowel disease is no different in pregnancy, with a few important exceptions.
Assessment of inflammatory bowel disease in pregnancy should rely on clinical factors such as abdominal pain, stool frequency, and rectal bleeding because pregnancy can affect laboratory indices such as haemoglobin concentration, erythrocyte sedimentation rate, and serum albumin. C reactive protein is not normally raised in pregnancy so it is valuable for assessing women with Crohn’s disease and ulcerative colitis. Abdominal radiography should be used if the clinical situation warrants it because the risks to the fetus are minimal. Flexible sigmoidoscopy seems to be safe in pregnancy15
;it does not induce labour or congenital abnormalities, but it should be used only when necessary.16
Commonly used drugs in inflammatory bowel disease include aminosalicylates, corticosteroids, immunomodulators such as azathioprine and methotrexate, and newer biological agents such as anti-tumour necrosis factor-α drugs. Pooled analysis of 19 mostly retrospective studies suggests that these drugs do not significantly increase the incidence of stillbirth, ectopic pregnancy, low
birthweight babies, or miscarriage.13
Congenital abnormalities may be higher in patients treated with aminosalicylate, anti-tumour necrosis factor-α, and azathioprine, but this may be related to disease activity rather than the drugs themselves.13
The table provides details of the safety profiles of drugs commonly used during pregnancy and breast feeding. These data come from the European Crohn’s and Colitis Organisation’s consensus statement on managing Crohn’s disease in pregnancy,16
and the recommendations are based on varying degrees of evidence, graded according to the Oxford Centre for Evidence Based Medicine. Readers should refer to the original article for further information.
Safety of commonly used drugs for inflammatory bowel disease during pregnancy and when breast feeding16
Most of the data on aminosalicylates and corticosteroids relate to oral preparations and, although information on topical preparations is limited, such preparations seem to be safe in pregnancy. Methotrexate is contraindicated in pregnancy, and prospective parents should be advised to discontinue this drug at least six weeks before conception.
Other agents including ciclosporin, tacrolimus, and thalidomide can be used in certain circumstances and under specialist supervision in inflammatory bowel disease and are not covered in this article.