Polycystic ovary syndrome (PCOS) is a condition that affects a woman’s hormone levels.
Women with PCOS produce higher-than-normal amounts of male hormones. This hormone imbalance causes them to skip menstrual periods and makes it harder for them to get pregnant.
Birth control pills and diabetes drugs can help fix the hormone imbalance and improve symptoms.
Read on for a look at the causes of PCOS and its effects on a woman’s body.
What is PCOS?
Many women have PCOS but don’t know it. In one study, up to 70 percent of women with PCOS hadn’t been diagnosed (2).
PCOS affects a woman’s ovaries, the reproductive organs that produce estrogen and progesterone — hormones that regulate the menstrual cycle. The ovaries also produce a small amount of male hormones called androgens.
The ovaries release eggs to be fertilized by a man’s sperm. The release of an egg each month is called ovulation.
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) control ovulation. FSH stimulates the ovary to produce a follicle — a sac that contains an egg — and then LH triggers the ovary to release a mature egg.
PCOS is a “syndrome,” or group of symptoms that affects the ovaries and ovulation. Its three main features are:
- cysts in the ovaries
- high levels of male hormones
- irregular or skipped periods
In PCOS, many small, fluid-filled sacs grow inside the ovaries. The word “polycystic” means “many cysts.”
These sacs are actually follicles, each one containing an immature egg. The eggs never mature enough to trigger ovulation.
The lack of ovulation alters levels of estrogen, progesterone, FSH, and LH. Estrogen and progesterone levels are lower than usual, while androgen levels are higher than usual.
Extra male hormones disrupt the menstrual cycle, so women with PCOS get fewer periods than usual.
PCOS isn’t a new condition. Italian physician Antonio Vallisneri first described its symptoms in 1721 (3).
Summary: Polycystic ovary syndrome (PCOS) affects up to almost 27 percent of women during their childbearing years ( 4). It involves cysts in the ovaries, high levels of male hormones, and irregular periods.
Doctors don’t know exactly what causes PCOS. They believe that high levels of male hormones prevent the ovaries from producing hormones and making eggs normally.
Genes, insulin resistance, and inflammation have all been linked to excess androgen production.
Studies show that PCOS runs in families (5).
It’s likely that many genes — not just one — contribute to the condition (6).
Insulin is a hormone the pancreas produces to help the body use sugar from foods for energy.
When cells can’t use insulin properly, the body’s demand for insulin increases. The pancreas makes more insulin to compensate. Extra insulin triggers the ovaries to produce more male hormones.
Women with PCOS often have increased levels of inflammation in their body. Being overweight can also contribute to inflammation. Studies have linked excess inflammation to higher androgen levels (9).
Summary: Doctors don’t know exactly what causes PCOS. They believe it stems from factors such as genes, insulin resistance, and higher levels of inflammation in the body.
Some women start seeing symptoms around the time of their first period. Others only discover they have PCOS after they’ve gained a lot of weight or they’ve had trouble getting pregnant.
The most common PCOS symptoms are:
- Irregular periods: A lack of ovulation prevents the uterine lining from shedding every month. Some women with PCOS get fewer than eight periods a year (10).
- Heavy bleeding: The uterine lining builds up for a longer period of time, so the periods you do get can be heavier than normal.
- Hair growth: More than 70 percent of women with this condition grow hair on their face and body — including on their back, belly, and chest (11). Excess hair growth is called hirsutism.
- Acne: Male hormones can make the skin oilier than usual and cause breakouts on areas like the face, chest, and upper back.
- Weight gain: Up to 80 percent of women with PCOS are overweight or obese (11).
- Male-pattern baldness: Hair on the scalp get thinner and fall out.
- Darkening of the skin: Dark patches of skin can form in body creases like those on the neck, in the groin, and under the breasts.
- Headaches: Hormone changes can trigger headaches in some women.
Summary: PCOS can disrupt the menstrual cycle, leading to fewer periods. Acne, hair growth, weight gain, and dark skin patches are other symptoms of the condition.
Having higher-than-normal androgen levels can affect your fertility and other aspects of your health.
Up to 80 percent of women with PCOS are overweight or obese (13). Both obesity and PCOS increase your risk for high blood sugar, high blood pressure, low HDL (“good”) cholesterol, and high LDL (“bad”) cholesterol.
This condition causes repeated pauses in breathing during the night, which interrupt sleep.
During ovulation, the uterine lining sheds. If you don’t ovulate every month, the lining can build up.
Summary: Hormone imbalances can affect a woman’s health in many ways. PCOS can increase the risk for infertility, metabolic syndrome, sleep apnea, endometrial cancer, and depression.
Doctors typically diagnose PCOS in women who have at least two of these three symptoms (17):
- high androgen levels
- irregular menstrual cycles
- cysts in the ovaries
Your doctor should also ask whether you’ve had symptoms like acne, face and body hair growth, and weight gain.
A pelvic exam can look for any problems with your ovaries or other parts of your reproductive tract. During this test, your doctor inserts gloved fingers into your vagina and checks for any growths in your ovaries or uterus.
Blood tests check for higher-than-normal levels of male hormones. You might also have blood tests to check your cholesterol, insulin, and triglyceride levels to evaluate your risk for related conditions like heart disease and diabetes.
An ultrasound uses sound waves to look for abnormal follicles and other problems with your ovaries and uterus.
Summary: Doctors diagnose PCOS if women have at least two of three main symptoms — high androgen levels, irregular periods, and cysts in the ovaries. A pelvic exam, blood tests, and ultrasound can confirm the diagnosis.
Pregnancy and PCOS
PCOS interrupts the normal menstrual cycle and makes it harder to get pregnant. Between 70 and 80 percent of women with PCOS have fertility problems (18).
This condition can also increase the risk for pregnancy complications.
However, women with PCOS can get pregnant using fertility treatments that improve ovulation. Losing weight and lowering blood sugar levels can improve your odds of having a healthy pregnancy.
Summary: PCOS can make it harder to get pregnant, and it can increase your risk for pregnancy complications and miscarriage. Weight loss and other treatments can improve your odds of having a healthy pregnancy.
Diet and lifestyle
Treatment for PCOS usually starts with lifestyle changes like weight loss, diet, and exercise.
Losing just 5 to 10 percent of your body weight can help regulate your menstrual cycle and improve PCOS symptoms (11, 20). Weight loss can also improve cholesterol levels, lower insulin, and reduce heart disease and diabetes risks.
Any diet that helps you lose weight can help your condition. However, some diets may have advantages over others.
Studies comparing diets for PCOS have found that low-carbohydrate diets are effective for both weight loss and lowering insulin levels. A low glycemic index (low-GI) diet that gets most carbohydrates from fruits, vegetables, and whole grains helps regulate the menstrual cycle better than a regular weight loss diet (21).
A few studies have found that 30 minutes of moderate-intensity exercise at least three days a week can help women with PCOS lose weight. Losing weight with exercise also improves ovulation and insulin levels (22).
Exercise is even more beneficial when combined with a healthy diet. Diet plus exercise helps you lose more weight than either intervention alone, and it lowers your risks for diabetes and heart disease (23).
Summary: PCOS treatment starts with lifestyle changes like diet and exercise. Losing just 5 to 10 percent of your body weight if you’re overweight can help improve your symptoms.
Birth control pills and other medicines can help regulate the menstrual cycle and treat PCOS symptoms like hair growth and acne.
Taking estrogen and progestin daily can restore a normal hormone balance, regulate ovulation, relieve symptoms like excess hair growth, and protect against endometrial cancer. These hormones come in a pill, patch, or vaginal ring.
Metformin (Glucophage, Fortamet) is a drug used to treat type 2 diabetes. It also treats PCOS by improving insulin levels.
One study found that taking metformin while making changes to diet and exercise improves weight loss, lowers blood sugar, and restores a normal menstrual cycle better than changes to diet and exercise alone (24).
Hair removal medicines
A few treatments can help get rid of unwanted hair or stop it from growing. Eflornithine (Vaniqa) cream is a prescription drug that slows hair growth. Laser hair removal and electrolysis can get rid of unwanted hair on your face and body.
Surgery can be an option to improve fertility if other treatments don’t work. Ovarian drilling is a procedure that makes tiny holes in the ovary with a laser or thin heated needle to restore normal ovulation.
Summary: Birth control pills and the diabetes drug metformin can help bring back a normal menstrual cycle. Clomiphene and surgery improve fertility in women with PCOS. Hair removal medicines can rid women of unwanted hair.
When to see a doctor
See a doctor if:
- You’ve missed periods and you’re not pregnant.
- You have symptoms of PCOS, such as hair growth on your face and body.
- You’ve been trying to get pregnant for more than 12 months but haven’t been successful.
- You have symptoms of diabetes, such as excess thirst or hunger, blurred vision, or unexplained weight loss.
If you have PCOS, plan regular visits with your primary care doctor. You’ll need regular tests to check for diabetes, high blood pressure, and other possible complications.
Summary: See your doctor if you’ve skipped periods or you have other PCOS symptoms like hair growth on your face or body. Also see a doctor if you’ve been trying to get pregnant for 12 months or more without success.
The bottom line
PCOS can disrupt a woman’s menstrual cycles and make it harder to get pregnant. High levels of male hormones also lead to unwanted symptoms like hair growth on the face and body.
Lifestyle interventions are the first treatments doctors recommend for PCOS, and they often work well. Weight loss can treat PCOS symptoms and improve the odds of getting pregnant. Diet and aerobic exercise are two effective ways to lose weight.
Medicines are an option if lifestyle changes don’t work. Birth control pills and metformin can both restore more normal menstrual cycles and relieve PCOS symptoms.