Follicle-stimulating hormone (FSH)

The production and secretion of FSH and LH are regulated by a balance of positive and negative feedback mechanisms involving the hypothalamic-pituitary axis, the reproductive organs, and the pituitary and sex steroid hormones. In women, follicle-stimulating hormone levels start to rise naturally around the menopausal period, reflecting a reduction in the function of the ovaries and a decline of oestrogen and progesterone production. However, at any other time, an increase in FSH levels are a sign of malfunction in the ovary or testis. A wide variety of disorders are associated with high FSH, including premature ovarian failure, gonadal dysgenesis, systemic lupus erythematosus, testicular failure, and Klinefelter syndrome. Low levels of FSH are also problematic and can lead to incomplete development at puberty for both men and women.