Epidemiology of Cardiovascular Disease in Pregnancy in Japan　― Analysis of a Nationwide Perinatal Database 2014–2023 ―

Background: Cardiovascular disease (CVD) is an increasingly important contributor to maternal morbidity and mortality worldwide, but contemporary nationwide data in Japan remain limited. Methods and Results: We conducted a retrospective cohort study using the Japan Society of Obstetrics and Gynecology Perinatal Database from 2014 to 2023. Among 2,189,852 registered pregnancies, 26,894 (1.23%) were complicated by maternal CVD. Pregnancies with CVD were compared with the low-risk population (pregnancies without any medical comorbidities; n=1,882,896). Pregnancies with CVD had lower parity and more frequently required cesarean delivery, general anesthesia, and labor analgesia than the low-risk population. Maternal cardiovascular complications, including hypertensive disorders of pregnancy, pulmonary embolism and pulmonary edema, occurred at higher rates among pregnancies with CVD. Maternal death was rare in both groups, but was more frequent in pregnancies with CVD than in the low-risk population (0.03% vs 0.01%, P<0.001). Neonatal outcomes were generally similar between groups. Conclusions: In this nationwide registry analysis, approximately 1% of pregnancies in Japan were complicated by maternal CVD. Women with CVD underwent more obstetric and anesthetic interventions and had a modestly higher risk of maternal morbidity and mortality. These findings underscore the importance of continued registry surveillance and may help inform risk-stratified perinatal management.