The follicle-stimulating hormone (FSH) is a hormone made by the pituitary gland, a small gland located on the underside of the brain. The FSH blood test measures the level of FSH in the bloodstream. The test is used to evaluate fertility issues, the health of reproductive organs (ovaries or testicles), or pituitary function. FSH works closely with another hormone called luteinizing hormone to control sexual functions. In women, FSH helps manage the menstrual cycle and stimulates the ovaries to produce eggs. In men, FSH stimulates the production of sperm. In children, FSH is involved with the development of sexual features.

The FSH blood test is usually performed at a doctors office, health clinic, hospital, or lab. The test involves taking a blood sample from a vein in the arm using a small needle. If you are a woman of childbearing age, your healthcare provider may want you to have the test done on certain days of your menstrual cycle. No special preparation is usually required for the test, but your doctor will tell you if you must stop taking any medications or supplements before the test.

The FSH test is used in different ways, depending on whether you are a woman, man, or child. In women, the test is most often used to help find the cause of infertility, find out if there is a proble...