On-Field Methodological Approach to Monitor the Menstrual Cycle and Hormonal Phases in Elite Female Athletes.

Objectives: Currently, there are no guidelines for implementing the monitoring of menstrual status, including the natural menstrual cycle (NC) or oral contraception (OC), in a sport setting. We aimed to provide a feasible, on-field methodological approach for monitoring NC and OC in female athletes.

Methods: We developed a smartphone app with daily questionnaires to monitor both NC and OC phases in 19 elite female soccer players (23.