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P702 The effect of disease activity on adverse birth outcomes in a nationwide cohort of woman treated with biologics for chronic inflammatory bowel disease during pregnancy

H. Kammerlander*1, J. Nielsen1, J. Kjeldsen2, T. Knudsen3, S. Friedman4, B. Nørgård1

1University of Southern Denmark, Centre for Clinical Epidemiology, Odense, Denmark, 2University of Southern Denmark, Department of Medical Gastroenterology, Odense, Denmark, 3University of Southern Denmark, Department of Medical Gastroenterology, Esbjerg, Denmark, 4Massachusetts and Harvard Medical School, 4. Crohn’s and Colitis Centre, Brigham and Women’s Hospital, Boston, United States


Most patients with inflammatory bowel disease (IBD) are diagnosed at 15–30 years of age, which coincides with the peak years of fertility and pregnancy. Biological therapy, primarily TNFα-blockers, is used for moderate-to-severe disease activity in IBD and for maintenance of remission. Biologics are also used in pregnant women with IBD to prevent maternal disease activity, as activity during pregnancy is thought to have a negative effect on birth outcomes. However, the documentation for this is still sparse. We examined the association between disease activity in pregnancy and adverse birth outcome amongst IBD women with underlying moderate-to-severe disease treated with biologics.


We used the Danish health registries to identify a nationwide cohort of IBD women treated with biologics during pregnancy or 3 months before conception in the period of January 1, 1998, to December 31, 2014. Thereafter, all medical records were reviewed for clinical details. The exposed were defined as women who had disease activity during pregnancy; mild or moderate/severe disease (moderate/severe disease defined as; more than 4 bowel movement/day and/or blood in stools and/or abdominal pain), and the unexposed cohort as women without disease activity. Outcomes were low birth-weight (LBW = < 2 500 g), preterm birth (< 37 weeks of gestation), and congenital abnormalities (CA). Analyses were performed separately for women with ulcerative colitis (UC) and Crohn’s disease (CD).


In total, 219 women with singleton births were included. Of these, 81 women (37.0 %) remained in remission, and 138 women (63.0%) had a disease flare during pregnancy. Further, 49 women had UC, and 170 had CD. In CD women, the results only indicated a tendency towards increased risk of preterm birth. In the exposed UC cohort, 5 women had a child with LBW; all of these women gave birth preterm. Additionally, 11 women (28.9%) had a preterm birth in the exposed UC cohort, corresponding to OR = 4.07 (95% CI 0.463–5.75). Of these 11 women, 8 experienced moderate/severe disease activity, 7 of these in second and third trimester, followed by treatment with biologics as relapse prophylaxis. See Table 1 for more details.

Table 1 Adverse birth outcomes in women with ulcerative colitis and Crohn’s disease


In CD women, we did not find that disease activity significantly increased the risk of adverse birth outcomes. In UC women, increased disease activity was associated with a 4-fold increased risk of preterm birth. Overall, 28.9% of UC women with active disease, the majority of whom had moderate/severe activity, delivered preterm.