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In women with normal ovarian function, the pituitary gland releases certain hormones during the menstrual cycle, which causes a small number of egg-containing follicles in the ovaries to begin maturing. Usually, only one follicle — a sac that's filled with fluid — reaches maturity each month.

When the follicle is mature, it bursts open, releasing the egg. The egg then enters the fallopian tube where a sperm cell might fertilize it, resulting in pregnancy.

Premature ovarian failure results from one of two processes — follicle depletion or follicle disruption.

Follicle depletion

Causes of follicle depletion include:

  • Chromosomal defects. Certain genetic disorders are associated with premature ovarian failure. These include Turner's syndrome, a condition in which a woman has only one X chromosome instead of the usual two, and fragile X syndrome, a major cause of intellectual disability (intellectual development disorder), formerly called mental retardation.
  • Toxins. Chemotherapy and radiation therapy are the most common causes of toxin-induced ovarian failure. These therapies may damage the genetic material in cells. Other toxins such as cigarette smoke, chemicals, pesticides and viruses may hasten ovarian failure.

Follicle dysfunction

Follicle dysfunction may be the result of:

  • An immune system response to ovarian tissue (autoimmune disease). Your immune system may produce antibodies against your own ovarian tissue, harming the egg-containing follicles and damaging the egg. What triggers the immune response is unclear, but exposure to a virus is one possibility.
  • Unknown factors. If you develop premature ovarian failure through follicular dysfunction and your tests indicate that you don't have an autoimmune disease, further diagnostic studies may be necessary. An exact underlying cause often remains unknown.
Feb. 12, 2014