OBJECTIVES: This study aimed to understand the status quo of medical treatments and pregnancy outcomes in patients with Takayasu arteritis (TAK) and children's birth outcomes. METHODS: This study retrospectively enrolled patients with TAK who conceived after the disease onset and were managed at medical facilities participating in the Japan Research Committee of the Ministry of Health, Labour, and Welfare for Intractable Vasculitis. RESULTS: This study enrolled 51 cases and 68 pregnancies during 2019-21. Of these, 48 cases and 65 pregnancies resulted in delivery and live-born babies. The median age of diagnosis and delivery was 22 and 31 years, respectively. Preconception therapy included prednisolone (PSL) in 51 (78.5%, median 7.5 mg/day), immunosuppressants in 18 (27.7%), and biologics in 12 (18.5%) pregnancies. Six cases underwent surgical treatment before pregnancy. Medications during pregnancy included PSL in 48 (73.8%, median: 9 mg/day), immunosuppressants in 13 (20.0%), and biologics in 9 (13.8%) pregnancies. TAK relapsed in four (6.2%) and eight (12.3%) pregnancies during pregnancy and after delivery, respectively. Additionally, 13/62 (20.9%) preterm infants and 17/59 (28.8%) low-birth-weight infants were observed, and none had serious postnatal abnormalities. CONCLUSIONS: Most pregnancies in TAK were manageable with PSL at ≤10 mg/day. Relapse during pregnancy and postpartum occurred in <
20% of pregnancies.