How is it used?When is it requested?What does the test result mean?Is there anything else I should know?
FSH is often used in conjunction with other tests (
LH,
testosterone,
oestradiol, and
progesterone) in the investigation of
infertility in both men and women. FSH levels are also useful in the investigation of menstrual irregularities (irregular periods) and to aid in the diagnosis of pituitary gland disorders. In children, FSH and LH are used to diagnose delayed or precocious (early) puberty.
In women and men, FSH and
LH are requested as part of the investigation of
infertility and pituitary gland disorders. FSH may also be used to determine if a woman has reached the
menopause. FSH levels also help to determine the reason a man has a low sperm count. In children, FSH and LH may be requested when a boy or girl does not appear to be entering puberty at an appropriate age (either too late or too soon).
What does the test result mean?
In women, FSH and
LH levels can help to tell the difference between primary ovarian failure (failure of the ovaries themselves) and secondary ovarian failure (failure of the ovaries due to disorders of either the pituitary gland or the hypothalamus in the brain). Increased levels of FSH and LH are consistent with primary ovarian failure. Some causes of primary ovarian failure are listed below.
Developmental defects:
- Ovarian agenesis (failure to develop ovaries)
- Chromosomal abnormality, such as Turner’s syndrome
- Ovarian steroidogenesis defect, such as 17 alpha hydroxylase deficiency
Premature ovarian failure due to:
Chronic anovulation (failure to ovulate) due to:
When a woman enters the 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 or hypothalamic problem.
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:
- Gonadal agenesis (failure to develop testes)
- Chromosomal abnormality, such as Klinefelters syndrome
Testicular failure:
- Viral infection (mumps)
- Trauma
- Radiation therapy
- Chemotherapy
- Autoimmune disease
- Germ cell tumour
Low levels of FSH are consistent with pituitary or hypothalamic disorders.
In young children, high levels of FSH and LH and development of secondary sexual characteristics at an unusually young age are an indication of precocious (early) puberty. This is much more common in girls than in boys.
Is there anything else I should know?
FSH results can be increased with use of certain drugs, such as cimetidine, clomiphene, digitalis, and levodopa. FSH results can decrease with oral contraceptives (the pill), phenothiazines, and hormone treatments.
