PREMATURE OVARIAN FAILURE
The diagnosis of premature
ovarian failure applies to the approximately 1% of women who experience
menopause before the age of 40 years. The
diagnosis should be suspectedin a young woman with hot flushes and other
symptoms of hypo-estrogenism and secondary amenorrhea (e.g., a woman seeking
treatment for infertility). The diagnosis is confirmed by lab-oratory
findings of menopausal FSH levels. Interestingly, hot flushes are not as common
as might be expected in this group of patients. The diagnosis has profound
emotional implications for most patients, especially if their desires for
childbearing have not been fulfilled, as well as metabolic and constitutional
implications. There are many causes of premature loss of oocytes and premature
menopause; some of the more common causes are discussed below. Given its
potential dramatic impact, premature ovarian failure demands a careful workup
in order to identify the under-lying cause and permit appropriate management.
Several factors influence a
woman’s reproductive life span. Genetic information that determines the length
of a woman’s reproductive life is carried on the distal long arm of the X
chromosome. Partial deletion of the long arm of one X chromosome results in
premature ovarian failure. Total loss of the long arm of the X chromosome, as
seen in Turner syndrome, results in ovarian failure at birth or in early
childhood. When suspected, these diagnoses can be established by careful
mapping of the X chromosome.
Some women with premature ovarian
failure have an ade-quate number of ovarian follicles, yet these follicles are
resistant to FSH and LH. A number of pregnancies have been reported in women
with the gonadotropin-resistant ovary syndrome during the administration of
exogenous estrogen. This fact supports a role for estrogens in stimu-lating FSH
receptors in the ovarian follicles.
Some women develop autoantibodies against thyroid, adrenal, and ovarian endocrine tissues. These autoantibod-ies may cause ovarian failure. Occasionally these women respond to hormone therapy with subsequent resumption of ovulation.
Women who
smoke tobacco can undergo ovarian failure some 3 to 5 years earlier than the
expected time of menopause. It is estab-lished that women who
smoke metabolize estradiol primar-ily to 2-hydroxyestradiol. The 2-hydroxylated
estrogens are termed catecholestrogens
because of their structural sim-ilarity to catecholamines. The
catecholestrogens act as anti-estrogens and block estrogen action. The
mechanism for premature ovarian failure in smokers is unknown. However, the
effects of smoking should be considered in smokers who are experiencing
symptoms of estrogen deficiency.
Alkylating cancer
chemotherapeutic agents affect the membrane of ovarian follicles and hasten
follicular atre-sia. One of the consequences of cancer chemotherapy in
reproductive-age women is loss of ovarian function. Young women being treated
for malignant neoplasms should be counseled of this possibility and advised
that they may be candidates for follicular retrieval and cryopreservation as a
means for attempting future pregnancy.
Surgical removal of the uterus
(hysterectomy) in repro-ductive-age women is associated with menopause some 3
to 5 years earlier than the expected age. The mechanism for this occurrence is
unknown. It is likely to be associated with alteration of ovarian blood flow
resulting from the surgery.
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