Also Known As
PCOS
Stein-Leventhal Syndrome
This article was last reviewed on
This article waslast modified on June 12, 2018.
What is polycystic ovary syndrome?

Polycystic ovary syndrome (PCOS) is a condition associated with hormone imbalances that affects women. Though the underlying cause of PCOS is not known or well understood, it is believed that an imbalance of sex hormones and resistance to the effects of the hormone insulin are the main problems. These problems result in a characteristic group of signs, symptoms and complications such as excess facial and body hair, irregular menstrual periods, infertility, and insulin resistance.

PCOS is the most common hormone disorder in women and one of the leading causes of infertility, affecting roughly 5-10% of women of childbearing age. The condition can affect girls as young as 11. Because the signs and symptoms often seem unrelated and the diagnostic criteria are not yet clear, most women are not diagnosed until they are in their 20's or 30's. It appears to run in families. Women with sisters who have PCOS are twice as likely to have the condition.

Though the diagnostic criteria are not yet clear, women usually have at least two of the following to be diagnosed with PCOS:

  • Overproduction of male hormones (androgens)
  • No release of eggs from the ovaries (no ovulation)
  • Polycystic ovaries—polycystic literally means "many cysts." A main feature of PCOS is that eggs are not released from a woman's ovaries. Instead, fluid builds up around the eggs, forming sacs (cysts). Though this feature is the origin of the name of the disorder, not all women diagnosed with PCOS have polycystic ovaries.

Hormone Imbalance
Though called "male hormones," androgens are normally produced in small amounts by a woman's ovaries and adrenal glands. However, when there is even a slight overproduction of male hormones, such as testosterone, a woman can experience signs and symptoms such as excess facial and body hair (hirsutism), acne, and weight gain.

These hormonal imbalances can also disrupt a woman's monthly menstrual cycle and cause irregular periods. When this happens, ovulation or egg release may be inhibited. If ovulation does not occur, a woman cannot conceive and she experiences fertility problems.

In PCOS, both ovaries tend to be enlarged, as much as three times their normal size. Eggs that do not mature fully are not released during ovulation and the immature eggs remain in the ovary as pearl-sized, fluid filled sacs. Over the course of time, many cysts may develop into what looks like a string of beads when viewed through ultrasound imaging. In as many as 90% of women with PCOS, an ultrasound of the ovaries will reveal cysts.

When a woman is not menstruating or ovulating, an insufficient amount of the hormone progesterone is produced. This hormonal imbalance can lead to an overgrowth of the lining of the uterus (endometrial hyperplasia) and can increase a woman's risk of developing endometrial cancer. Women with PCOS who do ovulate and become pregnant tend to have an increased risk of complications such as miscarriage.

Insulin Resistance
It is thought that insulin resistance may be a key factor in PCOS. Insulin helps transport glucose into the body's cells. where it is needed for energy production. When there is resistance to insulin's effect, the body tries to compensate by making even more insulin and releasing it in the blood (hyperinsulinemia). Some believe that too much insulin may cause the ovaries to increase androgen production, which in turn causes the symptoms associated with PCOS.

Most women with PCOS have some degree of insulin resistance, weight gain, and abnormal blood lipid levels. However, insulin resistance tends to be even more pronounced in women who are obese and do not ovulate. These conditions put those with PCOS at a higher risk of developing type 2 diabetes, high blood pressure (hypertension), and cardiovascular disease.

Accordion Title
About PCOS
  • Signs and Symptoms

    Women who have polycystic ovary syndrome (PCOS) may experience a wide variety of signs and symptoms that may vary in severity and over time. Often, the signs and symptoms seem unrelated, which can make recognizing the disorder difficult.

    Some examples of signs and symptoms include:

    • Irregular menstrual periods, abnormal uterine bleeding, or lack of menstruation (amenorrhea)
    • Ovaries with multiple cysts (polycystic); enlarged ovaries
    • Pelvic pain
    • Excess facial and body hair growth (hirsutism)
    • Weight gain or obesity, especially with fat distribution in center of the body
    • Acne, darkening or thickening of the skin (acanthosis nigricans) and/or skin tags in the armpits or neck
    • Deeper voice (rare)
    • Male pattern baldness, thinning hair

    Some of the complications associated with PCOS include:

  • Tests

    There is no specific test that can be used to diagnose polycystic ovary syndrome (PCOS) and there is no widespread agreement on what the diagnostic criteria should be. A health practitioner will typically evaluate a combination of clinical findings such as a woman's signs and symptoms, medical and family history, and physical exam as well as laboratory test results to help make a diagnosis.

    Some testing may done to rule out other possible causes of PCOS-like symptoms before a PCOS diagnosis can be made. For example, adrenal or ovarian tumors or an overgrowth in adrenal tissue called adrenal hyperplasia can also cause an overproduction of male hormones in women.

    Laboratory Tests

    Several hormone tests may be used to evaluate a woman for PCOS:


    A few tests may help rule out other conditions with similar signs and symptoms:


    Other blood tests may be done to check a woman's health and detect any complications that might develop:


    Non-Laboratory Tests
    A pelvic ultrasound (transvaginal and/or pelvic/abdominal) is used to evaluate enlarged ovaries. Ultrasounds are often used to look for cysts in the ovaries and to see if the internal structures appear normal. In PCOS, the ovaries may be 1.5 to 3 times larger than normal and characteristically have more than 12 or more follicles per ovary measuring 2 to 9 mm in diameter. Often the cysts are lined up on the surface the ovaries, forming the appearance of a "pearl necklace." The follicles tend to be small and immature, thus never reaching full development. The ultrasound helps visualize these changes in more than 90% of women with PCOS, but they are also found in up to 25% of women without PCOS symptoms. (For more, see RadiologyInfo.org: Pelvic ultrasound.)

    Laparoscopy may be used to evaluate ovaries and sometimes used as part of surgical treatment. (For more, see MedlinePlus: Pelvic laparoscopy.)

  • Treatment

    There is no cure for polycystic ovary syndrome (PCOS) and it does not go away on its own. Treatment of PCOS is aimed at reducing its symptoms and preventing further complications. Options depend on the type and severity of the individual woman's symptoms and her desire to become pregnant.

    • Diet, exercise, and maintaining a healthy body weight may help many women manage the symptoms of PCOS. These lifestyle changes are recommended to help decrease insulin resistance. Weight reduction can also decrease testosterone, insulin, and LH levels. Regular exercise and healthy foods will help lower blood pressure and cholesterol as well as improve sleep apnea problems. Refraining from smoking cigarettes or other tobacco products also may lower androgen levels.
    • Drugs such as metformin may be prescribed to treat insulin resistance and diabetes. Metformin may also help to regulate menstrual periods and encourage ovulation.
    • Waxing, shaving, depilatory, and electrolysis or laser treatments may be used to remove excess facial and body hair.
    • Antibiotics or retinoic acids may be used to treat acne.
    • Oral contraceptives may be prescribed to help normalize menstrual periods.
    • Other medications may also be prescribe to:
      • Stabilize hormone levels
      • Treat more severe acne and/or excess hair
      • Encourage or induce ovulation
      • Decrease the risk of endometrial cancer


    For more on treatment, see the resources in  the Related Content section.

View Sources

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

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