Premature ovarian failure

Description, Causes and Risk Factors:

Abbreviation: POF.

Women have had two ovaries which are situated in the pelvis either side of the uterus or womb. The ovaries have two functions: to produce eggs and hormones. The ovary comprises four cell types, germ cells, granulosa cells, theca cells and support cells. The integrity of germ cells and granulosa cells is closely interdependent so their survival and failure occur in parallel. In some causes of ovarian the defect is primarily in germ cells, X chromosome abnormalities for instance, while others the granulosa cells are the main target, eg. FSH receptor mutations.

Premature ovarian failure refers to a loss of normal function of your ovaries before the age of 40. If your ovaries fail, they do not produce normal amounts of the hormone estrogen or release eggs regularly. Infertility is a common result.

Premature ovarian failure is sometimes referred to as premature menopause, but the two conditions are not exactly the same. Women with premature ovarian failure — also known as primary ovarian insufficiency — may have irregular or occasional periods for years and may even become pregnant. Women with premature menopause stop having periods and can't become pregnant.

Restoring estrogen levels in women with premature ovarian failure helps prevent some complications, such as osteoporosis, but infertility is harder to treat.

The cause of POF is usually idiopathic. Some cases of POF are attributed to autoimmune disorders, others to genetic disorders such as Turner syndrome and Fragile X syndrome. An Indian study showed a strong correlation between incidence of POF and certain variants in the inhibin alpha gene. In many cases, the cause cannot be determined. Chemotherapy and radiation treatments for cancer can sometimes cause ovarian failure. In natural menopause, the ovaries usually continue to produce low levels of hormones, but in chemotherapy or radiation-induced POF, the ovaries will often cease all functioning and hormone levels will be similar to those of a woman whose ovaries have been removed. Women who have had their tubes tied, or who have had hysterectomies, tend to go through menopause several years earlier than average, likely due to decreased blood flow to the ovaries. Family history and ovarian or other pelvic surgery earlier in life are also implicated as risk factors for POF.

There are two basic kinds of premature ovarian failure. Case 1) where there are few to no remaining follicles and case 2) where there are an abundant number of follicles. In the first situation the causes include genetic disorders, autoimmune damage, chemotherapy, radiation to the pelvic region, surgery, endometriosis and infection. In most cases the cause is unknown. In the second case one frequent cause is autoimmune ovarian disease which damages maturing follicles, but leaves the primordial follicles intact.[9] Also, in some women FSH may bind to the FSH receptor site, but be inactive. By lowering the endogenous FSH levels with ethinyl estradiol (EE) or with a GnRH-a the receptor sites are free and treatment with exogenous recombinant FSH activates the receptors and normal follicle growth and ovulation can occur. Since the serum anti-m