S1556 Safety of Biologic Therapies in Pregnant Women With Inflammatory Bowel Disease: A Retrospective Matched Cohort Study

Introduction: Inflammatory Bowel Disease (IBD) frequently affects women of reproductive age, and active disease during pregnancy elevates risks of adverse maternal and fetal outcomes. Biologic therapies are essential for managing moderate to severe IBD. While continuing many biologics during pregnancy is generally supported to maintain remission, concerns about placental transfer and neonatal impacts persist, particularly for newer agents with limited long-term infant data. This study aimed to assess the association between biologic exposure during pregnancy in women with IBD and specific adverse maternal and fetal outcomes compared to non-exposed pregnant women with IBD. Methods: This is a retrospective cohort study utilizing TriNetX, a US collaborative database, to identify pregnant women (>18 years old) with IBD. Treatment and non-treatment groups were created based on biologic therapies use during pregnancy. Propensity score matching (1:1) was employed to minimize bias by adjusting for demographics and relevant comorbidities. Odds ratios (OR) for miscarriage, preterm delivery, suspected poor fetal growth, cesarean section rates, hypertensive disorders, and fatty liver of pregnancy were calculated to compare matched cohorts. Results: A total of 795 patients were identified in the biologic therapies group and a total of 16,101 patients were identified in the non-biologic control group. After propensity score matching, 777 patients remained in each cohort. There was no statistical difference in maternal and fetal outcomes between the 2 groups. Specifically, these included miscarriage (OR 1.0, 95% CI 0.51-1.97), preterm delivery (OR 0.69, 95% CI 0.43-1.11), suspected poor fetal growth (OR 0.85, 95% CI 0.57-1.26), cesarean section (OR 1.03, 95% CI 0.74-1.42), hypertensive disorders of pregnancy (OR 0.81, 95% CI 0.55-1.19), and fatty liver of pregnancy (OR 1.0, 95% CI 0.41-2.42). Conclusion: In this retrospective cohort study, biologic therapies in pregnant patients with IBD appear to be safe, showing no increased risk of miscarriage, preterm delivery, suspected fetal growth restriction, hypertensive disorders of pregnancy, or cesarean delivery compared to the control group. These findings support the continued evaluation of biologics as a potentially safe option during pregnancy in IBD patients.