Children's Hospital Colorado

Polycystic Ovary Syndrome (PCOS)

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What is polycystic ovary syndrome (PCOS)?

Polycystic ovary syndrome (PCOS) is a health issue that can affect women and teens of reproductive age. This condition occurs when females have extra testosterone (a male hormone) in their body. The increased testosterone affects the menstrual cycle, hair growth, skin, weight and the ability to have children.

Despite its name, PCOS doesn’t create cysts on the ovaries. A cyst is a growth or collection of fluid that is treated very differently. The name of the condition instead refers to the cyst-like appearance that the ovary has. An ovary can take on a cyst-like appearance when someone does not ovulate regularly. Ovarian cysts occur due to different causes.

What causes polycystic ovary syndrome (PCOS)?

PCOS occurs when testosterone levels are higher than typical for females. Some of the reasons for higher testosterone levels can be complex and researchers continue to explore the various causes of higher testosterone levels. Doctors and researchers have linked PCOS to genetic factors (factors inherited from parents) as well as weight gain. More than half of those with PCOS have family members with either PCOS or type 2 diabetes.

New research suggests that many with PCOS are sensitive to insulin, which is called insulin resistance. Genetic factors can make the ovaries more sensitive to insulin, which causes them to produce more testosterone.

When weight gain is a cause of PCOS

For teens and young women who are overweight, decreased physical activity often contributes to weight gain, which increases the amount of insulin in the body. As a result, the ovaries release more testosterone. The extra testosterone causes the physical symptoms of PCOS, like excess hair growth on the face and body.

When genetic factors are the cause of PCOS

In women who are not overweight, doctors believe that the ovaries make too much testosterone due to genetic factors.

In all women with PCOS, the ovaries function differently. Typically, once a month, the ovaries make a follicle (where an egg grows). As the follicle grows, it makes hormones and then it releases an egg. This is commonly referred to as ovulation.

However, the ovary in a woman with PCOS makes many small follicles instead of one big one. The follicle looks like a cyst on an ultrasound and gives us the name “polycystic ovaries.” Although the follicles are harmless, they create an imbalance in hormone levels and affect ovulation. As a result, periods become irregular or stop altogether. 

Who gets polycystic ovary syndrome (PCOS)?

Genetics do play a role in causing PCOS, but the condition is also caused by weight gain and other factors that we have not yet discovered.

How common is PCOS?

About 5% to 10% of all women have PCOS.

What other conditions can PCOS be associated with?

Other conditions besides PCOS are linked to the hormones that cause higher levels of insulin and androgens (a group of hormones that are typically higher in males), and this can affect the entire body. Once we diagnose someone with PCOS, we also recommend they be tested for pre-diabetes, fatty liver disease and high cholesterol. PCOS can also be associated with mood issues like depression, anxiety and sleep problems.

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Get to know our pediatric experts.

Stephen Scott, MD

Stephen Scott, MD

Ob/Gyn Obstetrics & Gynecology

Veronica Alaniz, MD

Veronica Alaniz, MD

Ob/Gyn Obstetrics & Gynecology