9th February 2024

A 32-year-old female presents with a seven-month history of amenorrhoea.

A 32-year-old female presents with a seven-month history of amenorrhoea. She reports that her menstrual cycle had been relatively regular prior to this. She has been training vigorously for an upcoming marathon with increased exercise and strict caloric intake restrictions. She has typical secondary sexual characteristics.

Blood tests have shown low oestrogen and progesterone levels and low FSH and LH levels. The imaging of her brain is unremarkable. 

Which of the following organs has likely been affected, resulting in the hormonal imbalance responsible for this presentation?