BACKGROUND: As multiple Japanese academic societies have recently issued treatment guidelines for perinatal antidepressant treatments, it is considered worthwhile to evaluate the latest trends and continuation of antidepressant medication during pregnancy to optimize antenatal prescriptions. METHODS: The prevalence, trend, and continuation of antidepressant use during pregnancy in Japan from 2012 to 2023 were evaluated, using a large administrative claims database, in women whose pregnancies ended in live births. Annual changes were evaluated using a multivariate logistic regression model adjusted for maternal age at delivery. RESULTS: Of 179,797 women with a mean maternal age at delivery of 32.5 years, 1870 (1.04%) were prescribed antidepressants during pregnancy. The prevalence significantly increased (P <
0.0001) from 0.63% in 2012 to 1.67% in 2023. Antidepressants were prescribed to 1730 women (0.96%) during the first trimester. Of these, 670 (38.7%) were antidepressant continuers throughout pregnancy, showing a significant increase (P <
0.0001) from 19.51% in 2012 to 50.70% in 2023. The most frequently prescribed class of antidepressants during pregnancy was serotonin reuptake inhibitors (0.74%), especially sertraline (0.33%) and escitalopram (0.23%), with a significant increase in their annual prevalence. LIMITATIONS: Prescriptions for women whose pregnancies ended in abortion or stillbirth could not be evaluated. CONCLUSIONS: Given that antidepressant use and its continuation during pregnancy have become more common, it is important to further disseminate knowledge of the guidelines to healthcare professionals and women of childbearing age, including the promotion of preconception care and shared decision-making.