Menstrual characteristics among rheumatoid arthritis patients receiving Janus kinase inhibitor, biologics, or methotrexate.

Rheumatoid arthritis (RA) affects women during reproductive years, yet menstrual outcomes under disease-modifying antirheumatic drugs remain poorly investigated. Because the JAK-STAT pathway regulates both immunity and ovarian function, Janus kinase inhibitors (JAKi) might influence menstrual health. We performed a cross-sectional, retrospective study of reproductive-aged women with RA attending rheumatology and gynecology clinics. Eligible participants had been receiving stable therapy for at least three months. Treatment categories included JAKi, Tumor necrosis factor inhibitors (anti-TNF) agents, non-anti-TNF biologics, and methotrexate. A structured questionnaire retrospectively assessed menstrual characteristics prior to therapy and during treatment. Outcomes included amenorrhea, cycle frequency, flow, menorrhagia, and metrorrhagia. Standardized definitions were applied, and analyses included chi-square tests, McNemar's test, and logistic regression adjusting for disease activity. The cohort included 100 women with RA. Amenorrhea occurred in 10%, metrorrhagia in 18%, menorrhagia in 10%, and altered cycle frequency in 41%. A significant within-patient increase in amenorrhea was observed during therapy (p = 0.04), but no between-group differences were detected. Multivariable regression adjusting for BMI and disease activity confirmed that JAKi were not independently associated with amenorrhea compared with other treatments (adjusted OR 1.82, 95% CI 0.46-7.29). Menstrual disturbances affected a minority of patients across all treatment groups. These findings suggest that JAKi do not negatively impact menstrual health.