Hormonally, POF is defined by abnormally low levels of estrogen and high levels of FSH, which demonstrate that the ovaries are no longer responding to circulating FSH by producing estrogen and developing fertile eggs. The ovaries will likely appear shriveled. Age of onset can be as early as the teenage years but varies widely. If a girl never begins menstruation, it is called primary ovarian failure. The age of 40 was chosen as the cut-off point for a diagnosis of POF somewhat arbitrarily—as all women’s ovaries decline in function over time, an age needed to be chosen to distinguish usual menopause from the abnormal state of premature menopause. However, premature ovarian failure often has components to it that distinguish it from normal menopause. By the age of 40, approximately one percent of women have POF. Women suffering from POF usually experience menopausal symptoms, which are generally more severe than the symptoms found in older menopausal women.

Template:WikiDoc Sources