FOLLICLE-STIMULATING HORMONE (FSH) TEST
The Follicle-stimulating hormone (FSH) is important to the reproductive system. It is responsible for the growth of ovarian follicles in women. This test measures the level of follicle-stimulating hormone (FSH) in the blood. FSH is made by the pituitary gland, a small gland located underneath the brain. FSH plays an important role in sexual development and functioning.
- In men, FSH helps control the production of sperm. Normally, FSH levels in men do not change very much.
- In women, FSH helps control the menstrual cycle and stimulates the growth of eggs in the ovaries. FSH levels in women change throughout the menstrual cycle, with the highest levels happening just before an egg is released by the ovary. This is known as ovulation.
- FSH levels are usually low in children until puberty when levels begin to rise. In girls, it helps signal the ovaries to make estrogen. In boys, it helps signal the testes to make testosterone.
Too much or too little FSH can cause a variety of problems, including the inability to get pregnant (infertility), menstrual difficulties in women, low sex drive in men, and early or delayed puberty in children.
What is the FSH test used for?
FSH works closely with another hormone called luteinizing hormone. Together, they work to control sexual functions, so a luteinizing hormone test is often done along with an FSH test. These tests are used in different ways, depending on whether the patient is a woman, man, or child.
In women, these tests are most often used to:
- Find out if there is a problem with ovarian function
- Help find the cause of infertility
- Find the reason for irregular or stopped menstrual periods
- Confirm the start of menopause, or Perimenopause. Menopause refers to the time in a woman's life when her menstrual periods stop. Then she cannot become pregnant anymore. It usually begins when a woman is around age 50. Perimenopause is the period of transition before menopause. FSH testing may be done towards the end of this transition.
In men, these tests are most often used to:
- Help find the cause of infertility
- Find the reason for a low sperm count
- Find out if there is a problem with the testicles
In children, these tests are most often used to help diagnose early or delayed puberty.
- Puberty is considered early if it starts before age 9 in girls and before age 10 in boys.
- Puberty is considered delayed if it has not started by age 13 in girls and by age 14 in boys.
Who needs an FSH levels test?
A woman, may need this test if:
- She has been unable to get pregnant after 12 months of trying.
- Her menstrual cycle is irregular.
- Her monthly periods have stopped. The test may be used to find out if she has gone through menopause or are in perimenopause
A man, may need this test if:
- He has been unable to get his partner pregnant after 12 months of trying.
- His sex drive is decreased.
Both men and women may need testing if they have symptoms of a pituitary disorder. These include some of the symptoms listed above, as well as:
- Fatigue
- Weakness
- Weight loss
- Decreased appetite
A child may need an FSH test if he or she does not seem to be starting puberty at the right age (either too early or too late).
During an FSH levels test
Using a small needle, a health care professional will take a blood sample from a vein in the arm. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes not more than five minutes. Our doctors should have the results after a day or two of having the test.
The results will show the concentration of FSH in S.I unit of “milli-international units per milliliter” (mlU/ML). The healthy range varies depending on gender and age (and for women, whether in menstrual cycle or menopause).
Understanding the test results
The meaning of the FSH test results will depend on who the patient is (i.e.) a woman, man, or child.
In the case of women, high FSH levels may mean:
- Primary ovarian insufficiency (POI) - Also known as premature ovarian failure. POI is the loss of ovarian function before the age of 40.
- Polycystic ovary syndrome (PCOS) - a common hormonal disorder affecting childbearing women. It is one of the leading causes of female infertility.
- The patient has begun menopause or is in perimenopause
- Turner syndrome - A genetic disorder that affects sexual development in females. It often causes infertility.
- An ovarian tumor
Low FSH levels in a woman may mean:
- You are very underweight.
- The pituitary gland is not working correctly.
- The ovaries are not making enough eggs.
- There is a problem with the hypothalamus, a part of the brain that controls the pituitary gland and other important body functions.
High FSH levels in a man may mean:
- Damage to the testicles- As a result of chemotherapy, radiation, infection, or alcohol abuse.
- Klinefelter syndrome - A genetic disorder which affects sexual development in males. It often causes infertility.
Low FSH levels in a man may be due to:
- A disorder of the pituitary gland or
High FSH levels in children along with high levels of luteinizing hormone may mean :
- Puberty is about to start or has already started. If this is happening before age 9 in a girl or before age 10 in a boy (precocious puberty), it may be a sign of:
- A brain injury
- A disorder of the central nervous system.
Low FSH and luteinizing hormone levels in children may be a sign of delayed puberty.
Which may be caused by:
- A disorder of the ovaries or testicles
- An infection
- A hormone deficiency
- Turner syndrome in girls
- Klinefelter syndrome in boys
- Eating disorders
Our doctors may also check other hormone levels too like:
- Estrogen
- Luteinizing hormone (LH), which stimulates egg release
- Testosterone
NOTE! Certain drugs (including birth control and hormone treatments) can lower FSH levels. It would be prudent for the patient to tell the doctor what medicines he/she might currently be taking.