Image of polycystic ovary syndrome in the body.
Patient Resources

Polycystic Ovary Syndrome

January 23, 2022

Polycystic ovary syndrome (PCOS) is a hormone disorder defined by a group of signs and symptoms.  PCOS affects 7–10% of women of childbearing age and is the most common cause of infertility. In the United States, an estimated 5 to 6 million women have PCOS. PCOS is the most common hormonal disorder among women of reproductive age, but many women don’t know they have it. 

Endocrine Connection 

The exact causes of PCOS are unknown. It is thought that there are many potential causes and these may be different between individual girls or women. Androgen excess (male hormone excess), seen in 60-80% of girls and women with PCOS, is a key problem in the disorder and likely comes from ovaries in most women. Insulin resistance or elevated insulin levels may worsen androgen excess. Abnormalities in how the brain or pituitary gland communicate with the ovaries may also lead to androgen overproduction. Other hormones from the ovary or fat tissue may also be involved.  

PCOS seems to be inherited. Female relatives or children of patients with PCOS are at increased risk for having PCOS. Environmental risk factorsincluding low birth weight, rapid weight gain in infancy, early pubic hair and puberty development, childhood obesity, excess adult weight, and unhealthy lifestyleare also important and may interact with genes to lead to PCOS. 

Along with irregular periods, the first signs of PCOS may be the growth of facial and male-patterned body hair (from KM: male-patterned body hair is not a term we typically use), acne, thinning scalp hair,  and weight gain. Weight gain, however, is not always present. Normal-weight women can also have PCOS. 

In addition to assessing signs and symptoms of PCOS, medical providers take a medical history, perform a physical exam, and check blood hormone levels (including testosterone). They may also perform an ovarian ultrasound. Other tests looking for complication of PCOS may also be done, such as glucose tolerance test or a mental health screening survey.  

Other disorders that mimic the clinical features of PCOS should be excluded: thyroid disease, high prolactin levels, and non-classical congenital adrenal hyperplasia. 

Signs of PCOS include: 

Male hormone (androgen) excess

  • Elevated testosterone levels in blood  
  • Clinical signs of androgen excess such as acne, hair on face and in male pattern on the body, and thinning hair on the scalp  

Problems with ovulation

  • Irregular or absent menstrual cycles  
  • Infertility 

Ultrasound findings

  • Large ovaries with many small follicles (which look like cysts, hence the name "polycystic"). These follicles are not cancerous.

Some conditions related to PCOS are potentially serious. Many women with PCOS have decreased sensitivity to insulin, the hormone that regulates glucose (sugar) in the blood. This condition, known as insulin resistance, is a major risk factor for type 2 diabetes. Women with PCOS often have type 2 diabetes, which occurs more frequently in women with PCOS. Signs of insulin resistance include weight gain (especially around the waist), acanthosis nigricans (skin thickening around the neck, armpits, belly, button, and other creases), and skin tags. 

The combination of type 2 diabetes mellitus, low HDL levels (good cholesterol), and high levels of LDL and triglycerides (bad cholesterol and blood fat) in women with PCOS may increase the risk of heart attack or stroke in women with PCOS.  

Women with PCOS who are overweight or obese can also develop a condition called obstructive sleep apnea, when breathing stops repeatedly during sleep. This condition can worsen the insulin resistance and cardiovascular problems of women with PCOS. 

Women with PCOS may also develop fat accumulation in the liver (non-alcoholic fatty liver disease), which can lead to liver damage (non-alcoholic steatohepatitis) and fibrosis over time.  

Because of irregular menstrual cycles and lack of ovulation, the lining of the uterus may not shed as often as it should. Left untreated, this may increase the risk of cancer of the uterine lining (endometrium). 

Adolescents and women with PCOS are also at higher risk for depression and anxiety. Women with PCOS, especially who are overweight, may experience pregnancy complications, including gestational diabetes, preterm delivery, or pre-eclampsia. 

While PCOS is not curable, symptoms are treatable with medications and changes in diet and exercise. Hormonal imbalances can be treated with birth control pills, androgen blocking medications, or medications that help the body use insulin better. For women whose infertility problems are not resolved with lifestyle changes alone, medications that improve ovulation (fertility drugs) may be helpful.

  • Do I have PCOS? 
  • What are my treatment options? 
  • What are the advantages and disadvantages of each of my treatment options? 
  • Am I likely to be infertile after treatment, or will I still be able to get pregnant? 
  • What lifestyle changes can I make to improve PCOS?  
  • Do I have any other health problems related to PCOS?  
  • Should I see an endocrinologist for my condition? 

Image of polycystic ovary syndrome infographic.

Endocrine Library >>

Last Updated:
Patient Resource

Find an Endocrinologist

Multiple doctors smiling
Our physician referral directory is comprised of over 6,500 members of the Society. The referral is updated daily with clinicians who are accepting new patients.
Patient Resource

Find an Endocrinologist

Our physician referral directory is comprised of over 6,500 members of the Society. The referral is updated daily with clinicians who are accepting new patients.

Back to top

Who We Are

For 100 years, the Endocrine Society has been at the forefront of hormone science and public health. Read about our history and how we continue to serve the endocrine community.