Polycystic Ovary Syndrome
Polycystic ovary syndrome (PCOS), formerly Stein-Leventhal syndrome, is a disorder in which women do not experience normal release of eggs from the ovaries, they have an abnormal production of male hormones, and their body is resistant to the effects of the hormone insulin. The disorder results in infertility, abnormal masculinization, and increased risk of developing heart disease and certain cancers.
The normal function of the female reproductive system is complex, requiring the interplay of different organ systems. One set of important organs are the ovaries. The ovaries are two small structures contained in the lower abdomen, on either side of the uterus, that contain small immature eggs, called ova. Ova are stored within the ovaries in individual structures called follicles.
In a monthly cycle, a part of the brain called the pituitary gland secretes two substances into the blood stream—lutenizing hormone (LH) and follicle-stimulating hormone (FSH). As certain levels of LH and FSH build in the blood stream, the follicles of the eggs begin to swell and grow, creating cysts. Eventually, the changing levels of LH and FSH cause one of the ovarian cysts to burst open, releasing a mature egg. This process by which an egg is released from the ovary is called ovulation.
Once a mature egg is released from the ovary, it passes into the fallopian tubes, tube-like structures that are passageways to the uterus. If sperm cells from the male are present within the fallopian tubes, they will join with the egg in a process called fertilization. The fertilized egg can then pass into the uterus and implant into the thickened wall of the uterus where it can develop into a fetus. If no sperm cells are present, the mature egg goes unfertilized and is lost, along with the thickened later of the uterus, in a monthly process called menstruation.
Polycystic ovary syndrome (PCOS), first described by I. F. Stein and M. L. Leventhal in 1935, is a disorder in which normal ovulation does not occur. The term "polycystic" derives from the fact that the egg-containing cysts in the ovaries do not burst open, resulting in enlarged ovaries containing many swelled cysts. The reason for this problem in ovulation is unclear, however several abnormalities have been characterized in women with PCOS. First, there is a disturbance in the production of LH and FSH by the pituitary, leading to altered levels of the substances in the blood stream. There is also evidence that the ovaries do not respond appropriately to the FH and LSH that is present. Second, there is an
abnormal over-production of male hormones, called androgens, by the ovaries and the adrenal gland. Finally, women with PCOS are resistant to the effects of the hormone, insulin. Insulin is a hormone made in the pancreas that is responsible for transport of sugar from the blood into the cells. While these abnormalities have been well characterized, it is unclear whether they cause PCOS, or whether they are a result the disease.
Women diagnosed with PCOS frequently have relatives with symptoms similar to that seen in the disorder. As a result of these observations, many scientists have proposed that genetic factors play a role in the disease. Over the past few decades, researchers have identified families in which PCOS appears to be inherited with an autosomal dominant or an X-linked pattern. However, these cases are rare and do not hold true for the majority of people with PCOS.
Current theories suggest that different genetic changes may result in PCOS or that multiple genetic factors are needed for the full manifestation of the disease. Abnormalities in several genes have been associated with PCOS, including mutations in the genes for follistatin (locus 5p14), 17-beta-hydroxysteroid dehydrogenase (locus 9p22), and a cytochrome P450 enzyme (locus 15q23-q24). Each of these genes plays a different role in the response to LH and FSH, or in the conversion of male hormones to female hormones, although their relationship to PCOS is unclear. Ongoing research is likely to identify further genetic mutations that are associated with PCOS.
Estimates of the prevalence of PCOS in the general population have ranged from 2-20% with recent studies suggesting that 3-6% of women of reproductive age are affected by the disorder. This makes PCOS one of the most common hormone disorders in women of reproductive age.
It is unclear whether this disease is distributed uniformly among different geographical areas and ethnic groups, however, studies performed in 1999 show the prevalence of this disorder in the United States is just over 3% in African-American females and almost 5% in Caucasian females. The prevalence of PCOS in Greek women was shown to be higher, nearly 7%.
Signs and symptoms
The first signs of PCOS tend to manifest at puberty. As a result of the failure to ovulate normally, young women with PCOS may fail to menstruate or menstruate only erratically. A small percentage of women may have normal menstrual cycles. Women affected with PCOS often experience infertility, an inability to become pregnant. Additionally, women with PCOS tend to gain weight, and 70% eventually become obese.
The overproduction of androgens leads to changes in the body that are more typical of male development. For example, approximately 70% of women with PCOS will show hair growth on the face, chest, stomach, and thighs (hirsuitism). Simultaneously, they show thinning of the hair more typical of male-pattern baldness. Other male characteristics, such as deep voice, acne, and increased sex drive may also be present, and affected women often have decreased breast size.
Women with PCOS do not respond appropriately to the hormone, insulin. As a result, 15% of women with PCOS may develop high levels of sugar in the blood later in life, a condition known as diabetes. Resistance to insulin is also associated with dark, warty skin growths in the groin and armpits, known as acanthosis nigricans.
Untreated PCOS is a risk factor for the development of several dangerous conditions. The hormone abnormalities in PCOS place women at considerable risk for endometrial cancer and possibly breast cancer. The risk of endometrial cancer is three times higher in women with PCOS than in normal women, and small studies suggest that the risk of breast cancer may by three to four times higher. PCOS also results in increased risk of high blood pressure, diabetes, and high cholesterol, all of which contribute to heart disease and stroke.
A diagnostic search for PCOS is usually initiated when women experience an absence of menstrual periods for at least six months, an inability to become pregnant, and/or abnormal hair growth or acne. A comprehensive
Blood tests can be performed that may yield results consistent with PCOS, including abnormal levels of LH and FSH (typically in a ratio of 3:1), abnormally high levels of androgens (testosterone, DHEA, DHEAS), abnormally high levels of insulin, and abnormally low levels of a substance called sex hormone-binding globulin. In addition, a physician may perform a diagnostic test called a "progesterone challenge". In this test, a physician administers a hormone called progesterone to the patient to determine if it will provoke menstruation. If menstruation does occur in response to the progesterone, it is likely that a patient has PCOS.
Finally, an ultrasound examination of the ovaries may be performed to determine if large cystic follicles can be documented. With this approach, the diagnosis of PCOS is based on the finding of more than eight enlarged follicles in the ovary.
Treatment and management
There is no cure for PCOS, thus treatment focuses on several goals, including the restoration of the menstrual cycle, blocking the effect of androgens, reducing insulin resistance, lowering the risk of cancer and heart disease, and possibly restoring ovulation and fertility.
In patients who do not desire pregnancy, hormones can be administered in the form of birth control pills, which may result in normal menstrual cycles, decreased
Other types of medication can be used to block the effects of androgens. When these medications are taken with birth control pills, 75% of women report decreased body hair growth. The most commonly used medications to block androgen effects are spironolactone (Aldactone), flutamide (Eulexin), and cyproterone (Cyprostat).
Treatment with medications that restore the body's normal response to insulin has been shown to decrease LH and androgen levels. Recent studies have demonstrated that such agents restore the menstrual cycle in 68-95% of patients treated for as short a time as four to six months. One of the most commonly used medications to improve the effects of insulin is metformin (Glucophage).
In patients who are trying to become pregnant, a physician can administer medications that will cause ovulation. The main medication used to induce ovulation is clomiphene citrate (Clomid). Ovulation is successful in approximately 75% of women treated with clomiphene, but only 30-40% of women will successfully become pregnant. Another medication, follitropin alpha (Gonal-F), has achieved pregnancy rates of 58-82%, but may cause more side effects and frequently results in more than one baby per pregnancy.
Some women who do not respond to medications may undergo surgery to remove portions of the ovary. For reasons that are not completely understood, removal of a portion of the ovary may result in some degree of normal menstrual cycles.
While medications and surgery may provide a degree of symptomatic relief for some women, other simultaneous strategies can increase their benefits. Behavior modifications, including weight reduction, diet and exercise, are recommended for all women with PCOS. As little as a 7% reduction in body weight can lead to a significant decrease in androgen levels and to the resumption of ovulation in obese women with PCOS. Cosmetic techniques, including electrolysis (destruction of the hair follicle using electricity) and laser therapy, may be used to decrease hair growth. Finally, women should be seen regularly for full physical examinations including pelvic exams to aid in the early detection of ovarian, breast, and uterine cancer and should be managed by an interdisciplinary health care team including a primary care physician, obstetrician/gynecologist and reproductive endocrinologist.
While PCOS is one of the most common hormone disorders in young women, proper diagnosis and treatment has greatly increased the quality of life in these individuals. Roughly half of women with PCOS will be able to achieve pregnancy, and about three-fourths will see reduction in masculine traits such as hair growth with proper medical treatment. Initiation of vigorous exercise and a restricted diet may result in even better outcomes. It should be noted that patients with PCOS are at higher risk of developing diabetes, heart disease, and certain cancers and should be seen regularly by a physician. Barring these developments, life span in patients with PCOS is approximately the same as the general population.
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Polycystic Ovarian Syndrome Association. PO Box 80517, Portland, OR 97280. (877) 775-PCOS. <http://www.pcosupport.org>.
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Oren Traub, MD, PhD