Menstrual disorders in female athletes

Menstrual Disorders in female athletes

• normal regular, healthy menstrual cycle (eumenorrhoea) is about 26-35 days
  • controlled by the hypothalamus and pituitary glands
    • divided into two phases by the occurrence mid-cycle of ovulation
      • first half of the cycle is the follicular phase and the second half the luteal phase
        • follicular phase is characterised by gradually increasing levels of oestrogen produced primarily by the ovaries
        • luteal phase is characterised by high concentrations of oestrogen and progesterone
  • in female athletes , menstrual cycle disturbances can progress from luteal phase defects to anovulation (no ovulation) and then to oligomenorrhoea (irregular cycles) and amenorrhoea
    • diagnosis of luteal phase defects is completed with measures such as a luteal phase less than 10 days long, inadequate progesterone concentration, ultrasound measurement of pre-ovulatory follicle diameter, and endometrial biopsy (1)
    • some suggest that amenorrhoea is a necessary criteria for the female athlete triad (2)
      • amenorrhoea is frequently defined as absence of menses for more than three cycles in a row
        • athletic amenorrhea is usually secondary amenorrhoea, but in sports where high levels of competition are reached at young ages, such as in gymnastics and figure skating, menarche may be delayed and therefore classified as primary amenorrhoea.
• the aetiology of menstrual disorders see in female athletes is incompletely understood
  • pulsatile release of luteinising hormone is decreased, which leads initially to luteal phase defects
  • also in comparison with sedentary women, women with luteal phase defects and amenorrhoea have higher concentrations of growth hormone and cortisol and lower concentrations of leptin, insulin, and triiodothyronine - the change in hormone profile reflect changes in metabolism, and thus to nutritional and metabolic status
    • "..if energy availability is low over a period of time, as indicated by these hormones, the menstrual cycle is temporarily "switched off" or suppressed to conserve energy..."(1)

Reference:

• 1) Birch K. Female athlete triad. BMJ 2005;330(7485):244-6
• 2) Schtscherbyna A et al. Female athlete triad in elite swimmers of the city of Rio de Janeiro. Brazil Nutrition 2009;25(6): 634-639.