A 19-year-old athlete (long-distance runner) presents with primary amenorrhea for 18 months despite menarche at age 14. She trains 6 hours/day and has a BMI of 17. The triad of low energy availability, menstrual dysfunction, and low bone mineral density in female athletes is termed the 'Female Athlete Triad.' The mechanism of hypogonadotropic hypogonadism in this condition is:

• A Increased GnRH pulse frequency due to chronic exercise stress
• B Primary ovarian failure caused by direct exercise-induced gonadotoxicity
• C Hyperprolactinaemia induced by exercise causing suppression of GnRH
• D Reduced GnRH pulse amplitude and frequency due to low leptin levels secondary to energy deficit ✓

Explanation

In the Female Athlete Triad, chronic energy deficit leads to low adipose tissue mass and markedly reduced leptin levels. Leptin is a permissive signal for the hypothalamic GnRH pulse generator; its deficiency leads to reduced GnRH pulse frequency and amplitude, resulting in hypogonadotropic hypogonadism with low LH and FSH, anovulation, and oestrogen deficiency. This is the functional hypothalamic amenorrhea (FHA) mechanism, similar to that seen in anorexia nervosa. It is reversible with restoration of energy availability.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.