Summary. Retrospective analysis of 82 pregnancies in women with either ulcerative colitis or Crohn's disease suggested that, in general, neither disease had a major effect on pregnancy outcome. The birthweights of babies born to women with inflammatory bowel disease were marginally lower than those born to women in a control group matched. for age and parity, but the difference was statistically significant only in women with Crohn's disease. In both disease groups there was a higher frequency of low haemoglobin levels in pregnancy than in the matched control groups. There were no statistically significant effects of ulcerative colitis or Crohn's disease on duration of pregnancy, mode of delivery or raised blood pressure and/or proteinuria. In the absence of a relapse, a diagnosis of inflammatory bowel disease should not influence obstetric management.