Abstract:Background: Polycystic ovary syndrome (PCOS) is a chronic medical condition characterized by ovulatory dysfunction, hyperandrogenism, and/or polycystic ovary morphology. Data on rates of PCOS among active-duty service members (ADSMs) are limited, despite high risk for medical comorbidities (e.g., obesity, type 2 diabetes) that could negatively impact ADSMs’ health and military careers. This study aimed to describe the incidence and prevalence of PCOS and possible PCOS (i.e., both ovulatory dysfunction and hyperandrogenism) among ADSMs. Methods: This retrospective cohort study accessed data from the Military Health System Data Repository between 2018 and 2022. ADSMs with a PCOS International Classification of Diseases, 10th Revision (ICD-10) code or ICD-10 codes indicative of irregular menstruation and hyperandrogenism within a 12-month period (i.e., possible PCOS) were identified. The yearly incidence and prevalence of PCOS/possible PCOS were computed per 10,000 female ADSMs, and Jonckheere-Terpstra tests for trend(s) were conducted. Results: During the surveillance period, 15,059 ADSMs met the criteria for PCOS or possible PCOS (55% white, 16% Hispanic/Latina; 44% aged 22–27 years; 85% enlisted, 13% officers). The yearly incidence rate of PCOS/possible PCOS ranged from 73 per 10,000 female ADSMs in 2018 to 103 per 10,000 female ADSMs in 2022 and did not change significantly (p = .33). The prevalence of PCOS/possible PCOS increased significantly (p = .01) from 210 per 10,000 female ADSMs in 2018 to 380 per 10,000 female ADSMs in 2022. Conclusion: Approximately 4% of ADSMs had a diagnosis of PCOS during the 5-year surveillance period, and about 1% of ADSMs newly met criteria for PCOS each year. More research is needed to determine the health care needs of ADSMs with PCOS.