FeMFit: Feasibility of tracking the menstrual cycle using digital questionnaires and wearable devices

INTRODUCTION: Despite its importance to female reproductive health and its impact on women's daily lives, the menstrual cycle and its effects on health remain poorly studied. Conventional clinical trials rely on infrequent in-person assessments. The aim of this study was to explore the technical feasibility of collecting longitudinal wearable and digital questionnaire data and its potential for gaining biological insights on the menstrual cycle. METHODS: This prospective observational cohort study was conducted online over twelve weeks using a digital study app and Fitbit inspire 2 devices. 42 individuals were recruited by their gynecologist in a practice in Berlin, Germany. Statistical analysis included descriptive statistics of user behavior and retention and comparative analyses of symptoms and sensor metrics at different phases of the menstrual cycle. RESULTS: We collected data of 114 ovulatory cycles from 33 participants, with nine out of 42 individuals dropping out within two weeks of study start. Participants reported a total of 2,468 symptoms during the luteal phase and menses. Despite difficulties with data completeness due to retention problems and drop-outs, the combined questionnaire and sensor data collection was technically feasible and produced interesting biological insights. Preliminary analysis of questionnaire and wearable data showed an increased heart rate in the mid and end luteal phase compared to menses and lower step count (mean 10,283 ±6,277) with strong symptoms of premenstrual syndrome (PMS, no/low PMS 11,694 ±6,458). CONCLUSIONS: We demonstrate the feasibility of using an app-based approach for collecting combined wearable and questionnaire data on menstrual cycles. Dropouts showed that engagement efforts would need to be improved for larger studies. Despite the challenges faced in collecting wearable data on consecutive days, the collected data provided valuable biological insights that should motivate further research at large scale. KEY MESSAGES: • Using an app-based approach for collecting combined wearable and questionnaire data on menstrual cycles was technically feasible and delivered interesting biological insights. • User engagement efforts need to be improved to reduce drop-outs and ensure consecutive data collection.