Changes in rheumatoid arthritis medication in pregnancy: a retrospective observational study using a Japanese claims database

OBJECTIVES: To examine changes in rheumatoid arthritis (RA) medication prescriptions during the peri-delivery period, and to explore recent RA prescription trends using a Japanese claims database. METHODS: This retrospective observational cohort study used an insurance claims database provided by JMDC Inc. We identified pregnant women with RA who delivered between April 2018 and October 2023. The outcome was the initiation or resumption of intensive treatment after delivery, defined as new or restarting of biologic disease modifying anti-rheumatic drugs (DMARDs), targeted synthetic DMARDs, oral corticosteroids (OCS), or methotrexate. RESULTS: We identified 229 mothers with RA and 246 deliveries. Intensive treatment was initiated in 55 (22.4%) deliveries. Continuation of the same prescription from before delivery was observed in 106 (43.1%) deliveries. The most frequent new prescription postpartum was methotrexate in 18 (7.3%) deliveries. OCS were the most commonly prescribed medications throughout the observation period. Tumour necrosis factor alpha inhibitors were prescribed at similar rates as OCS before pregnancy and in the first trimester, but declined during the second and third trimesters, and returned postpartum. CONCLUSIONS: The number of deliveries that required intensive treatment postpartum was lower than in previous studies. Our results suggest that the latest guidelines for pregnant women with RA help control disease activity.