Epidemiological data suggest that there is a small increase in the risk of Crohn’s disease in women who use the combined oral contraceptive pill,1-3 the relative risk being about twofold. On this basis, many physicians advise women with Crohn’s disease not to use this form of contraception. Is there really sufficient evidence to justify this advice? Unlike smoking,1 there is no clear evidence of an association between oral contraceptive use and the prevalence of Crohn’s disease. The available data are confounded by problems with study design and also the influence of smoking, as some studies have shown that smokers are more likely to use oral contraception. There is little information on whether the type of oral contraception may explain some of the differences observed, in particular the oestrogen dose and the length of use.

Patients with active inflammatory bowel disease are at increased risk of developing thromboembolic disease and there are also theoretical reasons to suppose that the pill might precipitate or exacerbate Crohn’s disease. High dose oral contraceptives, containing more than …