Impact of pregnancy on the clinical activity of Crohn's disease

Summary Background : The impact of pregnancy on Crohn's disease activity has been poorly investigated. Aim : To determine the effect of pregnancy on Crohn's disease activity from the retrospective analysis of a cohort of women who had a regular clinical follow-up. Methods : Seventy pregnancies occurring in 61 women were studied. The Harvey–Bradshaw index was determined during the four quarters preceding each pregnancy, the three quarters of pregnancy and the four quarters following delivery. Results : The mean Harvey–Bradshaw index during pregnancy [0.68 (0.18), mean (S.E.M.)] was significantly lower than that of the year preceding pregnancy [0.98 (0.16), P = 0.03] and that of the year following delivery [1.10 (0.17), P = 0.04]. In non-smoking women (48 pregnancies), there was no significant change of Harvey–Bradshaw index between these intervals. Whereas in those who smoked (22 pregnancies), most of whom reduced tobacco consumption during pregnancy, the mean Harvey–Bradshaw index during pregnancy was significantly reduced compared with that of the year following delivery [0.58 (0.20) vs. 1.60 (0.33), P = 0.01]. The use of drugs was significantly lower during pregnancy. Conclusions : Crohn's disease activity is mildly but significantly lower during pregnancy. The reduction of tobacco consumption during pregnancy in smoking women may play an important role in this improvement.