Description
Follicle-stimulating hormone (FSH) is made by the pituitary gland.
FSH controls the growth and maturation of womens ovarian follicles (eggs). At the time of menopause, the ovaries stop functioning and FSH levels rise.
In men, FSH stimulates the testes to produce mature sperm and it level is relatively constant in males after puberty.
FSH levels rise shortly after birth and then fall between 6 months and 2 years. Levels rise again before puberty.
This test is prescribed when a woman is having difficulty getting pregnant or is having irregular menstrual periods. Also the doctor thinks that there are symptoms of a pituitary or hypothalamic disorder or symptoms of ovarian (or testicular) disease. In children, if a there is delayed or earlier than expected sexual maturation.
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm. Sometimes urine test is also prescribed.
Purpose of the test
To evaluate pituitary function.
Both in women and men, FSH and LH tests are ordered as part of the workup of pituitary or gonadal disorders. FSH may be ordered to determine if a woman has reached menopause.
In children, FSH and LH may be ordered when a boy or girl has puberty at an appropriate age (either too late or too soon)
Reference range values
Females:
Follicular 3 – 11 U/L
Mid-Cycle 6 - 21 U/L
Luteal 1 – 9 U/L
Postmenopausal 22 – 153 U/L
Males: 1 – 11 U/L
Abnormal findings
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.
High livels of FSH and LH can indicate ovarian failure such as :
• Ovarian agenesis (failure to develop ovaries)
• Chromosomal abnormality, such as Turner’s syndrome
• Ovarian steroidogenesis defect, such as 17 alpha hydroxylase deficiency
These could be due to:
• Radiation
• Chemotherapy
• Autoimmune disease
On the other hand chronic anovulation (failure to ovulate) can be due to:
• Polycystic ovary syndrome (PCOS)
• Adrenal disease
• Thyroid disease
• Ovarian tumor
FSH levesl rise when a woman enters menopause.
Low levels of FSH and LH are can indicate a pituitary or hypothalamic problem both in women and men.
In men, high FSH levels are due to testicular failure due to developmental defects in testicular growth or to testicular injury due to:
• Gonadal agenesis
• Chromosomal abnormality, such as Klinefelters syndrome
• Viral infection (mumps)
• Trauma
• Radiation
• Chemotherapy
• Autoimmune disease
• Germ cell tumor
Some of the causes for High FSH levels in children are:
• Central nervous system lesions
• Hormone-secreting tumors
• Ovarian tumors or cysts
• Testicular tumors