Polycystic ovary syndrome (PCOS) is the most common cause of infertility in reproductive-age women and an important harbinger of metabolic disorders such as diabetes and heart disease. It affects an estimated 5 to 10 percent of females and is associated with an increased risk of diabetes and obesity, and as a result, an increased risk of cardiovascular disease. The syndrome is generally characterized by the presence of polycystic ovaries, hyperandrogenism (the condition caused by excess male hormones or male-like traits) and irregular ovulation and menstruation. The symptoms of PCOS can vary.
The syndrome was previously called Stein-Leventhal Syndrome after the physicians who first characterized it in the 1930s. It usually presents in young women or adolescents, and the main symptoms are irregular or absent periods and excess unwanted facial and/or body hair growth (hirsutism). As the term polycystic ovary syndrome suggests, the syndrome often is accompanied by enlarged ovaries containing multiple small painless “cysts” or tiny follicles about 1/8 to 1/4 inch in diameter.
During a normal menstrual cycle in which a woman ovulates (called an ovulatory cycle), a small number of follicles begin to grow. One becomes the biggest, or dominant, follicle. This dominant follicle then ruptures and releases the egg.
In women with PCOS, however, high levels of hormones called androgens (commonly known as “male hormones”) halt the normal hormonal process and the egg’s development. These halted or arrested follicles––whose appearance (via an ultrasound) is sometimes likened to a “string of pearls” on the outside border of the ovary––form the “cysts” observed in PCOS. These cysts are not tumors and do not require removal. Treatment of PCOS, instead, is through the use of lifestyle modifications and medication to treat symptoms.
Many, but not all, women with PCOS will have the polycystic-looking ovaries (which are often two to five times larger than normal ovaries) for which the syndrome is named, but it is possible to be diagnosed with the syndrome without having this sign. And not all women with polycystic-appearing ovaries will have PCOS.
While the biochemical imbalances that cause symptoms are becoming better understood, the trigger for PCOS is unknown. Some researchers believe that abnormal levels of the pituitary hormone LH and high levels of male hormones (androgens) prevent the ovaries from functioning normally. Others believe that the origin is in abnormalities in the genes that regulate the production of androgens or the action of insulin.
Some patients with PCOS experience excess insulin production from the pancreas, which can result from insulin resistance. Insulin resistance is a precursor to type 2 diabetes. The high levels of insulin in these women help stimulate the ovaries to overproduce androgens and may be the cause of PCOS in some women.
Insulin resistance in women with PCOS results from the fact that in these women the body’s cells don’t respond well to insulin. Insulin is a hormone produced by the pancreas. It regulates a range of functions, including controlling blood sugar and fats. With insulin resistance, the pancreas produces excessive amounts of insulin, leading to a condition called hyperinsulinism or hyperinsulinemia.
In addition to stimulating the ovaries to overproduce male hormones (called androgens), high levels of insulin can cause darkening of the skin around the neck and other crease areas, a condition called acanthosis nigricans, often accompanied by skin tags in these areas.
If the pancreas can’t produce enough insulin to compensate for the insulin resistance, glucose builds up in the blood, eventually leading to type 2 diabetes.
About 80 percent of obese women with PCOS have insulin resistance by age 40 and about 10 percent develop type 2 diabetes. Insulin resistance and an increased risk of diabetes is also a problem for normal weight women with PCOS, although less so than for obese women. For obese women with PCOS, their treatment plans should incorporate diet and exercise.
Up to 50 percent of women with PCOS also have sleep apnea, a condition that causes brief spells where breathing stops during sleep. Sleep apnea can worsen the degree of insulin resistance.
The most visible symptoms of PCOS stem from excessive levels of androgens, such as testosterone, produced by the ovaries and the adrenal glands. Androgens often are called “male hormones,” even though they are found in both men and women. They are usually present at higher concentrations in men and are an important factor in determining male traits and reproductive activity. Androgens include testosterone, dihydrotestosterone (DHT), androstenedione and dehydroepiandrosterone (DHEA) or the HS sulfated form (DHEA-S).
Excessive levels of these hormones, a condition called hyperandrogenemia, or their exaggerated action, called hyperandrogensim can lead to some of the most common symptoms of PCOS in women, including:
- Excess body or facial hair (hirsutism)
- Oily skin and acne
- Oligo-ovulation (irregular ovulation and menstruation)
- Scalp hair loss and balding (male pattern balding and androgenic alopecia)
But such symptoms alone are not enough to support a diagnosis of PCOS. They may only indicate the presence of hyperandrogenism, which can result from several conditions.
Women with PCOS ovulate irregularly and/or infrequently and often have irregular menstrual periods. Inducing a period is important because the hormone progesterone promotes the normal shedding of the uterine lining (i.e., menstruation), preventing the buildup of the uterine lining and reducing the risk of endometrial (uterine) cancer. However, progesterone is secreted by the ovaries only after ovulation occurs.
PCOS often is a cause of infertility due to failure to ovulate.
Women with PCOS are more likely to be overweight or obese, although the exact relationship is unknown. Excess weight worsens PCOS, but researchers do not yet know whether or not having PCOS makes patients more prone to obesity.
PCOS is mostly a genetic disorder. For example, an estimated 50 percent of sisters and 40 percent of mothers of patients with PCOS can be affected.
To date there is no cure for PCOS. Health care professionals usually address the most bothersome symptoms. Because of the complexity of the hormonal interactions, you may need to see an endocrinologist or a reproductive endocrinologist (especially if you are infertile and trying to conceive).