BACKGROUND AND AIMS: Inflammatory bowel disease (IBD) often affects patients in their fertile age. The aim of this study was to describe pregnancy outcome in a European cohort of IBD patients. As data are limited regarding the effect of pregnancy on disease course, our second objective was to investigate whether pregnancy influences disease course and phenotype in IBD patients. METHODS: In a European cohort of IBD patients, a 10-yr follow-up was performed by scrutinizing patient files and approaching the patients with a questionnaire. The cohort comprised 1,125 patients, of whom 543 were women. Data from 173 female ulcerative colitis (UC) and 93 Crohn's disease (CD) patients form the basis for the present study. RESULTS: In all, 580 pregnancies, 403 occurring before and 177 after IBD was diagnosed, were reported. The rate of spontaneous abortion increased after IBD was diagnosed (6.5% vs. 13%, p = 0.005), whereas elective abortion was not significantly different. 48.6% of the patients took medication at the time of conception and 46.9% during pregnancy. The use of cesarean section increased after IBD diagnosis (8.1% vs 28.7% of pregnancies). CD patients pregnant during the disease course, did not differ from patients who were not pregnant during the disease course regarding the development of stenosis (37% vs 52% p = 0.13) and resection rates (mean number of resections 0.52 vs 0.66, p = 0.37). The rate of relapse decreased in the years following pregnancy in both UC (0.34 vs 0.18 flares/yr, p = 0.008) and CD patients (0.76 vs 0.12 flares/yr, p = 0.004). CONCLUSIONS: Pregnancy did not influence disease phenotype or surgery rates, but was associated with a reduced number of flares in the following years.