For many women, irregular or infrequent menstrual cycles may not sound like such a bad thing. But a condition that can cause irregular periods - polycystic ovary syndrome, or PCOS - can present women with numerous health concerns, ranging from excess hair growth to fertility issues to an increased risk of heart disease and diabetes.

PCOS affects about one in 10 women of reproductive age, making it one of the more common hormonal abnormalities women experience during their reproductive years. Women often notice that something is wrong when they have irregular bleeding - either infrequent and very light or more frequent and heavy - and often excess hair growth, says Dan Lebovic, M.D., M.A., assistant professor of obstetrics and gynecology at the University of Michigan Medical School.

"If women are having irregular cycles, they should have their physician examine them either at their annual exam or sooner," says Lebovic, also the co-director of the U-M Health System Endometriosis Center. "PCOS can lead to serious health conditions, and the sooner it is detected, the better the chances that the PCOS can be treated effectively."

Polycystic ovaries occur when small cysts form on the inside of the ovary. This makes the ovary appear more plump than usual during surgeries or on imaging studies, Lebovic says, and creates multiple blebs (blisters) on top of the ovary in such a way that the ovary looks like an inverted golf ball.

Among women with PCOS, each cyst likely contains a small egg that cannot be released because the hormonal environment prevents that from happening. This leads to an endocrine, or hormonal, disorder in which the egg cannot be ovulated from the ovary, and therefore is kept inside each cyst.

This leads to irregular menstrual cycles, which can mean that a woman has a period fewer than 10 times a year, or even as little as just three or four times a year (without the use of birth control pills for the purpose of slowing or stopping the woman's periods).

The accompanying problems for women can be limited and mild, or broad-ranging and severe, Lebovic says.

Many patients have an increase in the growth of facial hair and weight gain due to the hormonal changes associated with PCOS, he notes. Some women with the condition also have higher levels of LDL cholesterol than the general public, which increases their likelihood of developing heart disease.

Many PCOS patients experience fertility problems simply because they can't produce an egg for fertilization every month. They have an increased risk of diabetes, with about 30 percent of PCOS patients suffering from pre-diabetes or insulin insensitivity and 10 percent having type II diabetes, Lebovic says. And PCOS patients may be at an increased risk for endometrial cancer, the cancer of the lining of the uterus.

Researchers are investigating the causes of PCOS, which may be an underlying insulin disorder that leads to the ovarian cysts, or which may begin as an enzyme malfunction in the ovary that leads to problems with insulin processing, Lebovic notes.

Diagnosis can be tricky, often because women don't always raise the issue of irregular periods with their physicians, Lebovic says. Sometimes the condition isn't discovered until a woman is having difficulty becoming pregnant, he says. A physical examination, ultrasound and blood tests can help diagnose the condition.

A form of treatment that can address the irregular periods, hair growth and fertility is metformin, Lebovic says. A few studies have shown that the medication - widely used to treat patients with diabetes and increasingly those with PCOS - can decrease the amount of the patient's excess hair growth and can increase the ovulation rate, increasing the woman's fertility. For women not trying to get pregnant, birth control pills are often used to treat PCOS.

Lebovic also notes that not all instances of polycystic ovaries are classified as PCOS. Nearly a third of women have polycystic ovaries, but a smaller number, about 10 percent, actually have PCOS.

Health conditions associated with PCOS

1. Women with polycystic ovary syndrome often experience irregular or infrequent menstrual cycles.
2. Many women with PCOS have excess hair growth on their faces, chests or abdomens.
3. PCOS can lead to fertility problems.
4. Women with PCOS have an increased risk of diabetes; 30 percent have pre-diabetes and about 10 percent have type II diabetes.
5. PCOS can increase the risk of heart disease, due in part to higher-than-normal levels of LDL cholesterol (also known as the "bad cholesterol").
6. Women with PCOS may have an increased chance of getting endometrial cancer, which is cancer of the lining of the uterus.