Follicle-stimulating hormone (FSH), produced by the pituitary gland, is pivotal in reproductive health. High FSH levels may signal fertility issues, while low levels can indicate pituitary or hypothalamic problems. The test helps in evaluating various conditions like hypogonadism, delayed puberty, infertility, polycystic ovarian syndrome (PCOS), amenorrhea, and hypothalamic-pituitary dysfunctions.