Prescribing in pregnant women with inflammatory bowel disease and its relationship to congenital malformations in Japan

Abstract Background and Aim Inflammatory bowel disease (IBD) frequently affects younger patients and poses various challenges concerning pregnancy and childbirth. Maintaining good disease control throughout pregnancy is crucial, but expectant and pregnant patients may worry about the fetal impact of medications, leading to treatment discontinuation due to uncertainty about this issue. This study investigated the real‐world drug‐prescribing practices for pregnant patients with IBD in Japan and their potential connection to major congenital malformations (MCMs). Methods Overall, 277 female IBD patients who gave birth between 2010 and 2019 were selected from the JMDC claims database. The prescribing patterns of IBD medications and MCMs in the patients' offspring were analyzed. Results Among pregnant IBD patients, 74.4% received at least one medication from 90 days before pregnancy to 90 days after delivery. Trends in medication prescriptions during pregnancy in 2010–2019 revealed consistent use of oral 5‐ASA, variable use of topical medications, a decrease in systemic steroids, and an increase in biologics. The prevalence of MCMs in children born to IBD‐affected mothers did not differ significantly between those who did and did not receive IBD medications (8.6% vs 6.8%). Although circulatory system MCMs were slightly more common in the IBD medication group (4.9% vs 1.4%), this difference was not significant. Logistic regression analysis did not reveal an association between MCM risk and first‐trimester use of IBD medications, including corticosteroids and biologics. Conclusions This study provides insights into medication patterns in pregnant IBD patients and suggests no increased risk of MCMs associated with first‐trimester IBD medication use.