Article Document Academic Article Information Content Entity Journal Article Continuant Continuant Entity Entity Generically Dependent Continuant 2025-06-25T11:12:35 RDF description of Hypothalamic-pituitary-ovarian axis suppression is common among women during US Army Basic Combat Training - http://repository.healthpartners.com/individual/document-rn37282 Observational Studies 10.1136/bjsports-2023-107716 British Journal of Sports Medicine <p>OBJECTIVE: Less than half of servicewomen report loss of menses during initial military training. However, self-reported menstrual status may not accurately reflect hypothalamic-pituitary-ovarian (HPO) axis suppression and may underestimate reproductive health consequences of military training. Our aim was to characterise HPO axis function during US Army Basic Combat Training (BCT) in non-hormonal contraceptive-using women and explore potential contributors to HPO axis suppression. METHODS: In this 10-week prospective observational study, we enrolled multi-ethnic women entering BCT. Trainees provided daily first-morning voided urine, and weekly blood samples during BCT. Urinary luteinising hormone, follicle stimulating hormone, and metabolites of estradiol and progesterone were measured by chemiluminescent assays (Siemens Centaur XP) to determine hormone patterns and luteal activity. We measured body composition, via dual-energy X-ray absorptiometry, at the beginning and end of BCT. RESULTS: Trainees (n=55) were young (mean (95% CI): 22 (22, 23) years) with average body mass index (23.9 (23.1, 24.7) kg/m(2)). Most trainees (78%) reported regular menstrual cycles before BCT. During BCT, 23 (42%) trainees reported regular menses. However, only seven trainees (12.5%) had menstrual cycles with evidence of luteal activity (ELA) (ie, presumed ovulation), all with shortened luteal phases. 41 trainees (75%) showed no ELA (NELA), and 7 (12.5%) were categorised as indeterminant. Overall, women gained body mass and lean mass, but lost fat mass during BCT. Changes in body mass and composition appear unrelated to luteal activity. CONCLUSIONS: Our findings reveal profound HPO axis suppression with NELA in the majority of women during BCT. This HPO axis suppression occurs among women who report normal menstrual cycles.<p> Hypothalamic-pituitary-ovarian axis suppression is common among women during US Army Basic Combat Training public 39598 Hormones 18 Stress document-rn37282 Prospective Studies Adverse Effects 58 22959 2024-09-14T19:18:35.867-05:00