This test measures the level of follicle-stimulating hormone (FSH) in your blood. FSH is

made by your pituitary gland, a small gland located underneath the brain. FSH plays an

important role in sexual development and functioning.High FSH levels can indicate primary

ovarian insufficiency (POI), the menopausal transition, or Turner syndrome. FSH levels

can also be higher in heavy smokers or drinkers or people with a vitamin D deficiency.