Also known as: Follicle-stimulating Hormone
Formal name: Follicle-stimulating Hormone, serum
The Test
How is it used?
FSH is often used in conjunction with other tests (LH, testosterone, estradiol, and progesterone) in the workup of infertility in both men and women. FSH levels are used to help determine the reason a man has a low sperm count. FSH levels are also useful in the investigation of menstrual irregularities and to aid in the diagnosis of pituitary disorders or diseases involving the ovaries or testes. In children, FSH and LH are used to diagnose delayed or precocious (early) puberty.
When is it ordered?
In women and men, FSH and LH are ordered as part of the workup of infertility and pituitary or gonadal disorders.
FSH may be ordered when a woman's menstrual cycle has stopped or become irregular, to determine if the woman has entered menopause.
In children, FSH and LH may be ordered when a boy or girl does not appear to be entering puberty at an appropriate age (either too late or too soon). Signs of early (precocious) puberty may include:
FSH may be ordered when a woman's menstrual cycle has stopped or become irregular, to determine if the woman has entered menopause.
In children, FSH and LH may be ordered when a boy or girl does not appear to be entering puberty at an appropriate age (either too late or too soon). Signs of early (precocious) puberty may include:
- Breast enlargement in females
- Growth of pubic hair
- Genitalia growth in males
- Beginning of menstruation in females
What does the test result mean?
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 pituitary or the hypothalamus). Increased levels of FSH and LH are consistent with primary ovarian failure. Some causes of primary ovarian failure are listed below.
Developmental defects:
Low levels of FSH and LH are consistent with secondary ovarian failure due to a pituitary 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 due to developmental defects in testicular growth or to testicular injury, as indicated below.
Developmental defects:
Low levels are consistent with pituitary or hypothalamic disorders.
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 can have many different underlying causes that need to be diagnosed and treated. Some of the causes include:
In delayed puberty, LH and FSH levels can be normal or below what is expected for a youth within this age range. A test for LH response to GnRH may need to be performed along with other testing to diagnose the reason for the delayed puberty. Some of the causes for delayed puberty can include:
Developmental defects:
- Failure to develop ovaries (ovarian agenesis)
- Chromosomal abnormality, such as Turner's syndrome
- Defect in the steroid production by the ovaries, such as 17 alpha hydroxylase deficiency
- Radiation
- Chemotherapy
- Autoimmune disease
- Polycystic ovary syndrome (PCOS)
- Adrenal disease
- Thyroid disease
- Ovarian tumor
Low levels of FSH and LH are consistent with secondary ovarian failure due to a pituitary 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 due to developmental defects in testicular growth or to testicular injury, as indicated below.
Developmental defects:
- Failure to develop gonads (gonadal agenesis)
- Chromosomal abnormality, such as Klinefelters syndrome
Low levels are consistent with pituitary or hypothalamic disorders.
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 can have many different underlying causes that need to be diagnosed and treated. Some of the causes include:
- Central nervous system lesions
- Hormone-secreting tumors
- Ovarian tumors or cysts
- Testicular tumors
In delayed puberty, LH and FSH levels can be normal or below what is expected for a youth within this age range. A test for LH response to GnRH may need to be performed along with other testing to diagnose the reason for the delayed puberty. Some of the causes for delayed puberty can include:
- Gonadal (ovary or testes) failure
- Hormone deficiency
- Turner's syndrome (chromosomal abnormality in girls)
- Klinefelter's syndrome (chromosomal abnormality in boys)
- Chronic infections
- Cancer
- Eating disorder (anorexia nervosa)
Is there anything else I should know?
FSH results can be increased with use of cimetidine, clomiphene, digitalis, and levodopa. FSH results can decrease with oral contraceptives, phenothiazines, and hormone treatments. FSH has been reported to increase with age and in smokers.
A recent nuclear medicine scan may interfere with results of the FSH test.
A recent nuclear medicine scan may interfere with results of the FSH test.
