Risk of Menstrual Dysfunction, Low Energy Availability, Eating Disorders and Injury in the First All-Female UK Military Team Rowing 3000 Miles Across the Atlantic.

Data on menstrual health, energy availability, and injury risk in women undertaking extreme ultra-endurance expeditions remain limited. We conducted a prospective cohort study of the first all-female UK military team competing in a 3000-mile transatlantic rowing race, aiming to characterize menstrual function, low energy availability (LEA) risk, eating disorder (ED) risk, and injury profiles. Four female British Army personnel completed the 46-day race. Menstrual symptoms, injuries, and illnesses were recorded daily, while reproductive, inflammatory, biochemical, and hematological markers were assessed before and after the race. LEA and ED risk were evaluated using the Low Energy Availability in Females Questionnaire and Brief Eating Disorder in Athletes Questionnaire, respectively. Analyses were primarily descriptive. Three athletes experienced amenorrhea during the expedition, including one with previously regular cycles. The fourth reported intermittent abnormal bleeding associated with injury and illness and screened positive for LEA risk before and after the race. Another athlete screened positive for ED risk at both time points. Most biomarkers remained stable post-race, whereas reproductive hormones showed consistent reductions in follicle-stimulating hormone and luteinizing hormone in all four participants, alongside increased oestradiol. These findings, based on a sample of four athletes, suggest that menstrual function may be sensitive to sustained physiological stress in extreme ultra-endurance settings, and support prospective monitoring in female ultra-endurance, military, and expeditionary populations.