Synonyms: FSH; FSH, Serum; Pituitary Gonadotropin

Why It Is Done

Help find the cause of infertility. Evaluate a woman's egg supply (ovarian reserve). Evaluate a man's low sperm count. Help evaluate menstrual problems, such as irregular or absent menstrual periods (amenorrhea). Determine whether a child is going through early puberty Determine why sexual features or organs are not developing when they should Help diagnose certain pituitary gland disorders, such as a tumor.

Test Overview

A follicle-stimulating hormone test measures the amount of follicle-stimulating hormone (FSH) in a blood sample. FSH is produced by the pituitary gland.

In women, FSH helps control the menstrual cycle and the production of eggs by the ovaries. The amount of FSH varies throughout a woman's menstrual cycle and is highest just before she releases an egg (ovulates).

In men, FSH helps control the production of sperm. The amount of FSH in men normally remains constant.

The amounts of FSH and other hormones (luteinizing hormone, estrogen, and progesterone) are measured in both a man and a woman to determine why the couple cannot become pregnant (infertility). The FSH level can help determine whether male or female sex organs (testicles or ovaries) are functioning properly.

How To Prepare

No special preparation is necessary.