What condition is characterized by markedly increased FSH levels?

The condition characterized by markedly increased FSH (follicle-stimulating hormone) levels is menopause. During menopause, a woman's ovaries produce significantly fewer hormones, particularly estrogen. This decline in estrogen leads to reduced negative feedback on the hypothalamus and pituitary gland, causing an increase in the release of FSH and luteinizing hormone (LH). The elevated levels of FSH are indicative of the body's attempt to stimulate ovarian function, which is diminished during this phase of life.

In contrast, in conditions like polycystic ovary syndrome, hormone levels can be imbalanced, often showing high LH but not necessarily high FSH. Hypothyroidism, while it can affect menstrual cycles and hormone balance, does not typically result in elevated FSH levels. Amenorrhea can have various causes, which may or may not involve changes in FSH levels depending on the underlying issue, but it does not consistently lead to the marked increases seen in menopause. Thus, menopause is the key condition characterized by markedly elevated FSH levels as the body transitions away from reproductive capability.