Premature Ovarian Failure (POF) is the cessation of menstrual periods and ovulation in women under the age of 40. Hormonally it is defined by abnormally low levels of estrogen and high levels of FSH, demonstrating that the ovaries are no longer responding to circulating FSH by producing estrogen. Age of onset can be as early as the teenage years but varies widely. By the age of 40, approximately one percent of women have POF. Women suffering from POF often experience menopausal symptoms and have a lifetime change of becoming pregnant between 0-10%. The only real option to archieve pregnancy is egg donation. Some cases of POF are attributed to an autoimmune disorder, while the cause of other cases remains unknown. Between 5 and 10 percent of women with POF become pregnant; it is unknown why ovulation can spontaneously reoccur. Currently no fertility treatment has been found to effectively increase fertility in women with POF.

Due to their low estrogen levels, women with POF are at an increased risk for osteoporosis. Hormone replacement therapy can restore estrogen levels to the normal range and can slow bone loss.

http://www.nichd.nih.gov/publications/pubs/pof/sub1.htm#what