[Original Short Communication]A 7-year longitudinal survey of valproate prescription in women of childbearing age in Japan using a publicly available National Insurance Claims Database Japan

[Abstract]【Introduction】Pharmacological treatments with valproate should be avoided where possible in childbearing-aged and pregnant women with epilepsy and bipolar disorder because they increase the risk of major congenital malformations. We previously reported a valproate prescription status in 2014 using publicly available National Insurance Claims Database (NDB Open Data Japan). This study aimed to evaluate the changes over time in valproate prescription using the NDB Open Data, which was released after the previous research (2015–2020). 【Methods】Following the previous study, We used prescription data from April 2015 to March 2021 from the NDB Open Data Japan. We examined the available prescription data of valproate in female and male outpatient data classified as total childbearing age (15–49 years), younger childbearing age (15–29 years), older childbearing age (30–49 years), and non-childbearing age (≥ 50 years). We determined the association between valproate prescription and sex at childbearing age, comparing to the non-childbearing age, and the odds ratio (OR) was estimated. 【Results】The proportion of valproate prescription for younger women of childbearing age (15–29 years) showed a significant downward trend from 2014 to 2020. Also, The OR of women of younger childbearing age (15–29 years) was decreased from 2014 to 2020 and 0.89 (in 2014), 0.77 (in 2015), 0.72 (in 2016), 0.69 (in 2017), 0.67 (in 2018), 0.63 (in 2019), and 0.63 (in 2020). 【Discussion】The proportion of valproate prescriptions for younger women of childbearing age (15–29 years) decreased every year between 2014 and 2019, likely influenced by factors such as safety concerns during pregnancy, changes in treatment guidelines favoring alternative medications, and improved patient education about the potential risks associated with valproate use during pregnancy.