Pregnancy-Onset Inflammatory Bowel Disease: A Subtle Diagnosis.

Background: Inflammatory bowel diseases (IBDs) are commonly diagnosed during the reproductive years. IBD first manifested during pregnancy (pregnancy-onset IBD [POIBD]) is still an undescribed entity. The aim of the study was to evaluate the characteristics and maternal and neonatal outcomes of patients with POIBD.

Methods: Data of all pregnant women with IBD within a single multidisciplinary referral clinic, IBD-MOM, between 2011-2016, were analyzed. Maternal and neonatal characteristics and outcomes were compared between the POIBD group and those diagnosed before pregnancy (non-POIBD).

Results: We identified 237 women, 31 (15%) from the POIBD group and 206 (85%) from the non-POIBD group. Eight (3.5%) patients experienced early spontaneous pregnancy loss, all in the non-POIBD group. The POIBD diagnosis occurred in 16 (52%) patients during the first trimester, 10 (32%) in second trimester, and 5 (16%) during third trimester. Diagnosis of ulcerative colitis (UC) was significantly more common in the POIBD group compared with the non-POIBD group (22/31, 71% vs 50/206, 24%, respectively, P < 0.001). More UC than Crohn's disease patients had active disease during pregnancy (69% vs 50%, P = 0.03, respectively). POIBD patients experienced vaginal delivery in 100% of births, compared with 164 (79.6%) in the non-POIBD group (P = 0.017). The mean gestational age at birth and the neonatal weight were similar among the study groups; 38.6 weeks and 3040 g for POIBD patients, compared with 38.7 weeks and 3055 g in the non-POIBD group.

Conclusions: POIBD is a unique clinical entity, and the diagnosis is mostly UC. However, the maternal and neonatal outcomes are similar.