Results of an FSH test are typically considered with results of other hormone tests, such as LH , estrogens, and/or testosterone.
As part of an infertility workup, a high or low FSH is not diagnostic but provides a piece of information on what may be the cause. For example, a hormone imbalance may affect a woman's menstrual cycle and/or ovulation. A health practitioner will consider all the information from the workup to establish a diagnosis. See the Infertility article for more on this.
In Women
FSH and LH levels can help to differentiate between primary ovarian failure (failure of the ovaries themselves) and secondary ovarian failure (failure of the ovaries due to disorders of either the or the ).
High levels of FSH and LH are consistent with primary ovarian failure. Some causes of primary ovarian failure are listed below.
Developmental defects:
- Failure to develop ovaries (ovarian agenesis)
- Chromosomal abnormality, such as
- Defect in the steroid production by the ovaries, such as 17 alpha hydroxylase deficiency
Premature failure of the ovaries due to:
Chronic failure to ovulate (anovulation) due to:
When a woman enters menopause and her ovaries stop working, FSH levels will rise.
Low levels of FSH and LH are consistent with secondary ovarian failure due to a pituitary disorder or hypothalamic problem. Low FSH serum levels have been associated with increased risk of ovarian cancer.
In Men
High FSH levels are due to primary testicular failure. This can be the result of developmental defects in testicular growth or to testicular injury, as indicated below.
Developmental defects:
Testicular failure:
- Viral infection (mumps)
- Trauma
- Radiation exposure
- Chemotherapy
- Autoimmune disease
- tumor
Low levels are consistent with pituitary or hypothalamic disorders. See the article on Pituitary Disorders for more information.
In Children
High levels of FSH and LH with the development of secondary sexual characteristics at an unusually young age are an indication of precocious puberty. This is much more common in girls than in boys. This premature development is usually due to a problem with the central nervous system and can have a few different underlying causes. Examples include:
- Central nervous system tumor
- Brain injury, trauma
- Inflammation within the central nervous system (e.g. meningitis, encephalitis)
- Brain surgery
Normal prepubescent levels of LH and FSH in children exhibiting some signs of pubertal changes may indicate a condition call "precocious pseudopuberty." The signs and symptoms are brought on by elevated levels of the hormones estrogen or testosterone. This may be caused by:
- Hormone-secreting tumors
- Adrenal gland tumors
- Ovarian tumors or cysts
- Testicular tumors
Normal FSH and LH levels with a few signs of puberty can also be a form of precocious puberty with no underlying or discernable cause or may just be a normal variation of puberty.
In delayed puberty, LH and FSH levels can be normal or below what is expected for a youth within this age range. Some of the causes for delayed puberty can include:
- Dysfunction of the ovaries or testicles
- Hormone deficiency
- Turner syndrome
- Klinefelter syndrome
- Chronic infections
- Cancer
- Eating disorder (anorexia nervosa)
FSH results can be increased with use of certain drugs, including cimetidine, clomiphene, digitalis, and levodopa. FSH results can be decreased with oral contraceptives, phenothiazines, and hormone treatments. FSH will also be low when women are pregnant. A recent nuclear medicine scan may interfere with results of the FSH test if it is measured by a radioimmunoassay, which is seldom used any more.