Trends in the estimated proportion of outpatients with menstrual disorders and the number of prescribed low-dose estrogen/progestin drugs in Japan: A descriptive study

Objectives: The aim of this study was to utilize publicly available government statistics to evaluate the trends in the estimated proportion of patients with menstruation-related diseases, including dysmenorrhea and endometriosis, and the number of low-dose estrogen/progestin drugs prescribed in Japan over approximately 20 years. Methods: The estimated proportion of outpatients with menstrual disorders, proportion of persons reporting irregular menstruation or menstrual pain, and number of prescriptions of low-dose estrogen/progestin drugs were extracted from the Patient Survey (1999–2023), Comprehensive Survey of Living Conditions (1998–2022), and National Database (NDB) Open Data (2014–2023), respectively. Results: According to the Patient Survey, the estimated proportion of outpatients with menstrual disorders, including dysmenorrhea, remained stable until 2011 and rose sharply after 2014. NDB data have demonstrated that the number of prescribed low-dose estrogen/progestin drugs covered by health insurance has increased since 2014. In contrast, the Comprehensive Survey of Living Conditions revealed that the rate of self-reported irregular menstruation or menstrual pain has continued to decline slightly over the past 20 years. Conclusions: The increased proportion of outpatients receiving treatment for menstrual disorders since 2014 coincides with the expansion of treatment options due to insurance coverage of low-dose estrogen/progestin drugs for dysmenorrhea. In addition, the launch of generic low-dose estrogen/progestin drugs since 2015 and the reduced economic burden due to lower drug prices may have led to an increased number of patients who continued treatment, resulting in an increased rate of follow-up visits. These findings provide a descriptive overview of national trends in menstrual health and healthcare utilization, but should be interpreted with caution given the limitations of aggregate data and the absence of individual-level or inferential statistical analysis.