Disease activity in pregnant women with Crohn's disease and birth outcomes: a regional Danish cohort study.

Objectives: CD is associated with increased risk of adverse birth outcomes, but existing studies have not assessed the impact of disease activity during pregnancy. We examined the impact of disease activity on birth outcomes: LBW, preterm birth, LBW at term, and CAs.

Methods: All births by CD women in North Jutland County, Denmark, from January 1, 1977 to December 31, 2005, were evaluated in a cohort study based on linkage between the Danish National Registry of Patients and the Medical Birth Registry. After identification of all births by CD women, review of medical records allowed collection of clinical details (including disease activity and drug therapy during pregnancy). The exposed cohort (N = 71) constituted pregnancies with low/moderate-high disease activity during pregnancy, and the unexposed cohort (N = 86) those with inactive disease. Logistic regression analyses were used to estimate the adjusted relative risks (with 95% confidence intervals) for adverse birth outcomes associated with disease activity in CD pregnancies. In subanalysis, we examined the impact of moderate-high activity.

Results: In women with disease activity, the adjusted risks of LBW, LBW at term, preterm birth, and CAs were 0.2 (0.0-2.6), 0.4 (0.0-3.7), 2.4 (0.6-9.5), and 0.8 (0.2-3.8), respectively. The crude risk of preterm birth was 3.4 (1.1-10.6) in those with moderate-high disease activity.

Conclusions: Disease activity during pregnancy only increased the risk of preterm birth (especially in those with high disease activity). Further research is needed to assess the critical impact of disease activity in larger cohorts of CD women.