A 24-year-old woman presents to your office with complaints of secondary amenorrhea since age 22. She had regular menses from age 13 to age 21, but only four periods during her last year of college....

A 24-year-old woman presents to your office with complaints of secondary amenorrhea since age 22. She had regular menses from age 13 to age 21, but only four periods during her last year of college. She reports no sexual intercourse since age 18. She gained 110 pounds during college, increasing from 140 to 250 pounds. Since age 22, she has lost 40 pounds, and is back down to 210 pounds. During this time she has increased her exercise to five times per week, 1 to 11⁄2 hours each time. Which of the following is the most likely cause of her secondary amenorrhea?

A. Elevated hCG leading to maintenance of her corpus luteum

B. Elevated circulating estrogen leading to a disruption in FSH/LH production by the pituitary

C. Sudden weight loss leading to hypogonadotropic hypogonadism

D. Excessive exercise leading to hypogonadotropic hypogonadism

E. Testicular feminization