Hypothalamic-pituitary-ovarian axis suppression is common among women during US Army Basic Combat Training

Area of Science:

• Reproductive Endocrinology
• Military Medicine
• Women's Health

Background:

• Self-reported menstrual status in servicewomen may not accurately reflect hypothalamic-pituitary-ovarian (HPO) axis suppression.
• Military training can have significant reproductive health consequences for women.
• Underestimating HPO axis suppression may lead to overlooking reproductive health issues.

Purpose of the Study:

• To characterize HPO axis function in women during US Army Basic Combat Training (BCT).
• To explore potential contributors to HPO axis suppression in this population.
• To assess the accuracy of self-reported menstrual status versus objective hormonal markers.

Main Methods:

• Prospective observational study of 55 multi-ethnic women entering BCT.
• Daily urine and weekly blood samples collected over 10 weeks to measure key reproductive hormones.
• Body composition assessed using dual-energy X-ray absorptiometry at study entry and exit.

Main Results:

• Despite 78% reporting regular cycles pre-BCT, only 12.5% showed evidence of ovulation during training.
• 75% of trainees exhibited no evidence of luteal activity (NELA), indicating significant HPO axis suppression.
• Changes in body mass and composition were not directly related to luteal activity.

Conclusions:

• Profound HPO axis suppression occurs in the majority of women during BCT, irrespective of reported normal menstrual cycles.
• Objective hormonal assessment reveals a higher prevalence of reproductive disruption than self-reports suggest.
• Findings highlight the need for targeted reproductive health monitoring in servicewomen undergoing intense training.