The effect of a seven-week online mindfulness intervention on the relationship between menstrual symptoms and mental health - A non-randomized controlled trial

Background Menstrual symptoms are common among physically active women and may affect their well-being and performance. Moreover, symptom frequency has been associated with mental health in previous studies. Although mindfulness-based interventions (MBI) have shown beneficial effects on psychological and physiological health outcomes, their potential role in the relationship between menstrual and mental health remains unclear. Therefore, this study examined whether participation in an MBI was associated with changes in this relationship. Methods 39 physically active students were split into an experimental group (EG; n = 14; 22.68 ± 2.23 years) and a control group (CG; n = 25; 22.76 ± 4.88 years), which conducted a baseline and post-intervention measurement, including a psychometric screening. The CG received no intervention during the study and was offered access to the intervention materials afterwards. Assessed constructs included the 21-item version of the Depression Anxiety Stress Scale and the Menstrual Symptom index (MSi). The MBI was developed based on mindfulness-based stress reduction, incorporating the dimensions of acting with awareness, non-judgmental acceptance, and present-moment attention. Results At baseline in the control group, MSi scores were positively associated with anxiety (B = 0.16; p = .004) and depression (B = 0.14; p = .012). No significant group × time interactions were observed for depression or stress. For anxiety, the group × time interaction was significant at the grand-mean MSi score (B = − 3.30; 95% CI [− 6.50, − 0.11]; p = .043), whereas the three-way interaction was not significant ( p = .054). Conclusion The results indicate that menstrual symptom frequency is associated with mental health outcomes in physically active students. Participation in the MBI was associated with changes in anxiety over time. However, the non-significant three-way interaction provided no conclusive evidence of moderation. These preliminary findings suggest potential benefits of MBI for anxiety in menstrual health context. Future studies should investigate programs that explicitly address menstrual-related aspects. Trial registration This study was registered as ‘Impact of an online mindfulness intervention on sleep quality in physically active students’ in the German Clinical Trials Register (DRKS) under the identifier DRKS00038462 on 13 November 2025. Retrospectively registered.