follicle-stimulating-hormone-fsh-levels-test

Why this test may be ordered

• To help find the cause of infertility in women and men
• To check for medical conditions that affect how the ovaries work
• To find the reason for irregular or stopped menstrual periods in women of childbearing age
• To find out when a woman is most likely to get pregnant
• To find out if menopause or perimenopause may have begun (usually around age 50 for menopause, around age 45 for perimenopause; testing may be needed if symptoms are unclear or if premature menopause before age 40 or early menopause before age 45 is suspected). In women age 45 or older, testing is usually not needed because high FSH is a normal sign of perimenopause/menopause, but may be done for medical reasons such as premature menopause, early menopause, or unclear symptoms. Also if a woman has less interest in sex than usual. In men, to find the reason for a low sperm count, loss of muscle and/or body hair, or less interest in sex than usual. In women and men, to help diagnose disorders of the pituitary gland or hypothalamus (which may cause fatigue, weakness, decreased appetite and/or weight loss). In children and teens, to find out if a medical disorder is causing early puberty (signs before age 8 in girls or age 9 in boys) or delayed puberty (no signs by age 13 in girls or age 14 in boys).

Preparation and collection

Women who have menstrual periods may need to be tested at a specific time during their menstrual cycle because FSH levels change throughout the month.

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. This usually takes less than five minutes.

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

Understanding results

To understand the results of your FSH test, your provider will consider your sex, age, symptoms, medical history, and the results of other hormone tests, especially your level of luteinizing hormone (LH). Your provider can explain what the results of your FSH test mean. Generally, in women and men:

• Higher levels of FSH: Often a sign of a condition in the reproductive glands (ovaries or testicles) that prevents them from making normal levels of sex hormones. The pituitary responds by making more FSH to try to get them to work properly. High FSH may also be a sign of a condition outside of the reproductive glands that affects how the glands work. Conditions linked to high FSH levels include: In women: ovaries that never developed normally, primary ovarian insufficiency (POI), polycystic ovary syndrome (PCOS), menopause or perimenopause, an ovarian tumor, thyroid diseases or adrenal gland disorders, a chromosomal disorder such as Turner syndrome. In men: a germ cell tumor, mumps, a physical injury to the testicles, a chromosomal disorder such as Klinefelter syndrome. In women and men: damage to the ovaries or testicles, which may be caused by autoimmune disease, radiation therapy and/or chemotherapy. Limitation: Results must be interpreted by a healthcare professional in the context of your overall health. High FSH alone does not diagnose a specific condition. Next step: Your provider will explain what your results mean and may recommend additional testing or follow-up.
• Lower than normal levels of FSH: Often a sign of a problem with the pituitary gland or hypothalamus. These problems may make it hard for your body to make FSH and LH. In women, low FSH levels may also be linked to rapid weight loss, being very underweight, or extreme exercise. Limitation: Results must be interpreted by a healthcare professional in the context of your overall health. Low FSH alone does not diagnose a specific condition. Next step: Your provider will explain what your results mean and may recommend additional testing or follow-up.
• In children with signs of early sexual development (before age 8 in girls or age 9 in boys): High levels of FSH and LH: The child has early puberty, also called precocious puberty. In most cases, the cause is unknown. But in certain cases, the cause is a problem in the brain, such as a brain tumor, a past brain injury, or a past brain infection such as meningitis or encephalitis. Limitation: Results must be interpreted by a healthcare professional. High FSH and LH alone do not diagnose the underlying cause. Next step: Your child's provider will explain what the results mean and may recommend additional testing or follow-up.
• In children with signs of early sexual development: Normal levels of FSH and LH: The child has a type of early puberty called peripheral precocious puberty. This often means that a disorder in the testicles, ovaries, or adrenal glands is causing higher than normal levels of estrogen or testosterone. Severe hypothyroidism and exposure to medicines that contain sex hormones may also cause this type of early puberty. Limitation: Results must be interpreted by a healthcare professional. Normal FSH and LH alone do not diagnose the underlying cause. Next step: Your child's provider will explain what the results mean and may recommend additional testing or follow-up.

• Results must be interpreted by a healthcare professional considering your sex, age, symptoms, medical history, and the results of other hormone tests, especially your level of luteinizing hormone (LH).
• At-home urine test kits can only find higher than normal FSH levels and should not be used to check whether you can become pregnant because they cannot accurately tell whether your ovaries are making eggs. If you use a home FSH test, discuss your symptoms and test results with your provider.

What to do next

If you have questions about test results, talk with your or your child's provider.

• Why is this test being ordered for me or my child?
• What do my FSH results mean in my specific situation?
• Do I need any other tests?
• What follow-up is needed based on these results?

Evidence source

U.S. National Library of Medicine: follicle-stimulating-hormone-fsh-levels-test