Polycystic ovary (or ovarian) syndrome – PCOS – is a hormonal condition that develops in women and girls of reproductive age. PCOS is a chronic condition that continues to affect women long after their childbearing years. PCOS can be treated, but there is no cure. Symptoms vary among women with PCOS, but menstrual irregularity, unwanted facial and body hair, and infertility are most common. Most women with PCOS lead normal lives without major complications and are able to minimize symptoms with a variety of treatments.
PCOS is the most common hormonal disorder in women of reproductive age. In PCOS, several hormones are overproduced or underproduced in the body, causing the variety of symptoms typical of PCOS. Hormones that become imbalanced in PCOS include androgens, insulin, and progesterone. Levels of these hormones differ among individuals with PCOS, accounting for different types of PCOS.
Androgens, sometimes referred to as "male hormones," include testosterone. In fact, everyone has androgens, but levels are normally much higher in men than in women. Hyperandrogenism is the term for elevated levels of androgens. In women, hyperandrogenism can affect the menstrual cycle and inhibit ovulation. Excess androgens are also the cause of many other PCOS symptoms, including acne, body and facial hair growth (hirsutism), and cysts in the ovaries.
Insulin is the hormone that enables the cells to take in and use blood sugar (glucose). Women with PCOS are often insulin resistant – their cells are not responsive or sensitive to insulin, and insulin does not work as well. If blood glucose levels become too high, the body will overproduce insulin in response. Too much insulin can then signal the body to make more androgens. High blood glucose (hyperglycemia) can also lead to the development of type 2 diabetes.
Progesterone is a hormone produced in the ovaries after ovulation. Progesterone prepares the uterus for receiving, implanting, and supporting a fertilized egg during pregnancy. Women with PCOS have too little progesterone, which can lead to irregular menstrual cycles and – if pregnancy occurs – miscarriages.
Hippocrates and other ancient Greek physicians described women with symptoms typical of PCOS – hirsutism (abnormal hair growth), acne, irregular menstrual periods, and infertility. Some researchers theorize that PCOS may have helped early women survive due to more efficient energy storage and lowered risk of maternal mortality. Much of what we know about PCOS has been discovered since the middle of the 20th century.
In 1935, American gynecologists Irving Stein, Sr., and Michael Leventhal observed the presence of ovarian cysts in women with anovulation – absent or infrequent ovulation. They named this condition Stein-Leventhal syndrome. For many years, the presence of ovarian cysts with anovulation were the diagnostic criteria of Stein-Leventhal syndrome. The syndrome was thought to be a rare condition. Gradually, the disorder came to be known as polycystic ovarian syndrome (PCOS). In the mid-1980s, researchers realized that not all women with PCOS have ovarian cysts, and that diagnostic criteria should include focus on anovulation and hyperandrogenism, not ovarian cysts. However, the name PCOS stuck.
It was not until the early 1990s at a National Institute of Health (NIH) conference on PCOS that formal diagnostic criteria were proposed. This sparked many scientists to study the pathophysiology of PCOS, and thousands of studies were published in the decade following the conference.
In 2003, standardized criteria were established at a conference of PCOS experts in Rotterdam. Known as the Rotterdam criteria, these guidelines are the gold standard for diagnosing PCOS. Scientists continue to study the relationship between PCOS and other conditions such as diabetes and heart disease.
An estimated 5 million women of reproductive age have PCOS in the U.S. Worldwide, between 6 and 12 percent of women are affected. PCOS is one of the leading causes of female infertility. PCOS often runs in families. Women who have a mother or sister with PCOS are more likely to have PCOS than a woman without an affected family member.
Ethnicity appears to play a role in the prevalence of PCOS. Women of Chinese descent have the lowest rate of PCOS. Those with European and Middle Eastern background are affected at higher rates. Women of African and Hispanic descent have the highest risk for PCOS. Read more about risk factors for PCOS.
Women with PCOS have an increased risk for a number of other health conditions. For women with insulin resistance, the risk of type 2 diabetes and cardiovascular disease is greatly increased. More than half of women with PCOS are diagnosed with type 2 diabetes by the age of 40. PCOS also increases the risk of stroke, hypertension (high blood pressure), sleep apnea, obesity, and endometrial cancer.
Women with PCOS are more likely to develop metabolic syndrome, a term that describes having a combination of hyperglycemia (high blood sugar), hypertension, high blood levels of cholesterol or triglycerides, and excess abdominal fat. Metabolic syndrome increases the risk for type 2 diabetes, stroke, and heart disease.
Can I get pregnant if I have PCOS?
Yes, women with PCOS can become pregnant. PCOS is one of the most common causes of infertility, but it is also treatable. Approximately 60 percent of women with PCOS become pregnant without medical help. In general, women with PCOS who require fertility treatments have the same average number of children as women without PCOS.
How is PCOS diagnosed?
PCOS is generally diagnosed through a combination of a physical examination, family history, blood tests, and imaging scans. PCOS is usually diagnosed by a family doctor or a gynecologist (specialist in the female reproductive system). Read more about PCOS diagnosis.
What are the symptoms of PCOS?
PCOS symptoms vary from woman to woman. The most common symptoms are menstrual irregularities, infertility, and unwanted facial and body hair. Read more about PCOS symptoms.
How is PCOS treated?
PCOS treatments fall into three main categories: medication, lifestyle changes, and surgery. Since PCOS can cause a wide variety of symptoms, many different kinds of drugs are used to treat it. Read more about PCOS treatments.
Does PCOS affect women of different races in different ways?
Researchers have found that ethnic background can be a determining factor in both the severity of symptoms and which complications women with PCOS experience. In one study of women with PCOS, women of Hispanic background were found to be more likely to have the most severe symptoms of hyperandrogenism such as acne, excess body and facial hair, and ovarian cysts than women of African or European descent. Hispanic women were also more likely to develop metabolic syndrome as a complication of PCOS. The same study found that non-Hispanic women of African background tended to have milder PCOS symptoms than women of Hispanic or European descent.