Polycystic Ovary Syndrome (PCOS)

Definition - What does Polycystic Ovary Syndrome (PCOS) mean?

Polycystic ovary syndrome (PCOS) is a hormone (endocrine) disorder in which a women's levels of estrogen and progesterone are out of balance. Women who have PCOS have two out of the three possible issues:

  • Multiple small cysts on ovaries (polycystic)
  • High levels of testosterone (hyperandrogenism)
  • Lack of ovulation (anovulation)

Some women with PCOS can get pregnant without assistance, while others have normal fertility restored by treatment with medications that encourage ovulation.

FertilitySmarts explains Polycystic Ovary Syndrome (PCOS)

PCOS is the most common ovulatory disorder, affecting about 5-10% of all women. The cause of PCOS is not known, although women who are overweight are at higher risk.

Women with PCOS show an imbalance of several hormones, including an excessive production of testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). The result is that ovulation occurs infrequently or not at all.

Signs and symptoms of PCOS include:

  • Absent or infrequent menstrual periods. Women with PCOS may have periods longer than 35 days, or may not menstruate at all for months at a time.
  • Acne. The hormone imbalances that interfere with ovulation can cause breakouts of acne, even in older adult women.
  • Excessive hair growth (hirsutism). Women with PCOS may observe the unusual growth of hair on the face, breasts, belly, and other areas of the body.
  • Signs of insulin resistance. Although insulin resistance and its symptoms can occur without PCOS, it is more common in women with PCOS. Symptoms of insulin resistance can include melanin production resulting in dark patches of skin in the neck, armpits, or inner thigh, as well as high blood sugar readings.
To confirm a diagnosis of PCOS, doctors may order blood work to test blood hormone levels. Many doctors consider a blood test showing abnormal hormone levels, combined with symptoms of PCOS, as sufficient for a diagnosis. Doctors may also perform an ultrasound to look for ovarian cysts. These cysts are ovarian follicles that do not develop normally due to the body's hormone imbalance. Instead of bringing an egg to maturity normally, they may grow larger than usual and remain in the ovary.


PCOS may be diagnosed in girls shortly after menarche (first period) or may appear later in life. The syndrome sometimes appears in adult women following substantial weight gain.

The mechanism of interaction between the insulin and reproductive hormone pathways in women is not well-understood. Weight gain and insulin resistance appear to be both a risk factor for and a cause of, PCOS.

In some women, treatment with the blood sugar-regulating drug metformin restores normal ovulation. The medication clomiphene can also restore ovulation in women with PCOS. The highest rates of restored ovulation in studies to date have been seen in women treated with metformin and clomiphene together.

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