Symptoms of PCOS often start around the time of the first menstrual period. Sometimes symptoms develop later after you have had periods for a while.

The symptoms of PCOS vary. A diagnosis of PCOS is made when you have at least two of these:

Irregular periods. Having few menstrual periods or having periods that aren’t regular are common signs of PCOS. So is having periods that last for many days or longer. For example, you might have fewer than nine periods a year. And those periods may occur more than 35 days apart. You may have trouble getting pregnant.

Too much androgen. High levels of the hormone androgen may result in excess facial and body hair. This is called hirsutism. Sometimes, severe acne and male-pattern baldness can happen, too.

Polycystic ovaries. Your ovaries might be bigger. Many follicles containing immature eggs may develop around the edge of the ovary. The ovaries might not work the way they should.

PCOS signs and symptoms are typically more severe in people with obesity.

The exact cause of PCOS isn’t known. Factors that might play a role include:

Insulin resistance. Insulin is a hormone that the pancreas produces. It allows cells to use sugar. If cells become resistant to the action of insulin, then blood sugar levels can go up. This can cause your body to make more insulin to try to bring down the blood sugar level, called insulin resistance.

Too much insulin might cause your body to make too much of the male hormone (androgen) You could have trouble with ovulation, the process where eggs are released from the ovary.

One sign or insulin resistance is dark, patches of skin on the lower part of the neck, armpits, groin or under the breasts. A bigger appetite and weight gain may be other signs.

Low-grade inflammation. White blood cells make substances in response to infection or injury. This response is called low-grade inflammation. Research shows that people with PCOS have a type of long-term, low-grade inflammation that leads polycystic ovaries to produce androgens. This can lead to heart problems.

Heredity. Research suggests that certain genes might he linked to PCOS. Having a family history of PCOS may play a role in developing the condition.

Excess androgen. With PCOS, the ovaries may produce high levels of androgen. Having, too much androgen interferes with ovulation. This means that eggs don’t develop on a regular basis and aren’t released from the follicles where they develop. Excess androgen also can result in hirsutism and acne.

Complications of PCOS can include:

Infertility

Gestational diabetes or pregnancy-induced high blood pressure

Miscarriage or premature birth

Nonalcoholic steatohepatitis — a severe liver inflammation caused by fat buildup in the liver

Metabolic syndrome — a cluster of conditions including high blood pressure, high blood sugar, and unhealthy cholesterol or triglyceride levels that significantly increase your risk of heart and blood vessel (cardiovascular) disease

Type 2 diabetes or prediabetes

Sleep apnea

Depression, anxiety and eating disorders

Increased risk of cancer of the uterine lining (endometrial cancer)

Obesity commonly occurs with PCOS and can worsen complications of the disorder.

There’s no single test to specifically diagnose polycystic ovary syndrome (PCOS). Your gynecologist is likely to start with a discussion or your symptoms, medications and any other medical conditions. Your doctor also may ask about your menstrual periods and any weight gain. A physical exam includes checking for signs of excess hair growth, insulin resistance and acne.

Your gynecologist might then recommend:

Pelvic exam. During a pelvic exam, your provider can check your reproductive organs for masses, growths or other changes.

Blood tests. Blood tests can measure hormone levels. This testing can exclude possible causes of menstrual problems or androgen excess that mimic PCOS. You might have other blood testing, such as fasting cholesterol and triglyceride levels. A glucose tolerance test can measure your body’s response to sugar (glucose). FSH and LH — hormone level

Ultrasound. An ultrasound can check the appearance of your ovaries and the thickness of the lining of your uterus. A wandlike device (transducer) is placed in your vagina. The transducer emits sound waves that are translated into images on a computer screen.

If you have a diagnosis of PCOS, your doctor might recommend more tests for complications. These tests can include:

Regular checks of blood pressure, glucose tolerance, and cholesterol and triglyceride levels

Screening for depression and anxiety

Screening for obstructive sleep apnea

PCOS treatment focuses on managing the things that are concerning you. This could include infertility, hirsutism, acne or obesity. Specific treatment might involve lifestyle changes or medication.

Your doctor will recommend weight loss through a low-calorie diet combined with moderate exercise activities. Even a modest reduction in your weight — for example, losing 5% to 10% of the body weight — might improve your condition. Losing weight may increase the effectiveness of medications your provider recommends for PCOS, and it can help with infertility.

To regulate your periods, doctor might recommend:

Combination birth control pills. Pills that contain both estrogen and progestin. This will decrease androgen production and regulate estrogen. Regulating your hormones can lower your risk of endometrial cancer and correct irregular bleeding, excess hair growth and acne.

Progestin therapy. Taking progestin for 10 to 14 days every 1 to 2 months can regulate your periods and protect against endometrial cancer. This progestin therapy doesn’t improve androgen levels and won’t prevent pregnancy. The progestin-only minipill or progestin-containing intrauterine device is a better choice if you also wish to avoid pregnancy.

To help you ovulate so that you can become pregnant, your health care provider might recommend:

Clomiphene. This oral medication is taken during the first part of your menstrual cycle.

Letrozole (Femara). This works to stimulate the ovaries.

Metformin. This medicine for type 2 diabetes improves insulin resistance and lowers insulin levels. If you don’t become pregnant using clomiphene, your provider might recommend adding metformin to help you ovulate. If you have prediabetes, metformin can slow the progression to type 2 diabetes and help with weight loss.

Gonadotropins. These hormone medications are given by injection.

To reduce excessive hair growth or improve acne, your health care provider might recommend:

Birth control pills. These pills decrease androgen production that can cause excessive hair growth and acne.

Spironolactone (Aldactone). This medication blocks the effects of androgen on the skin, including excessive hair growth and acne. Spironolactone can cause birth defects, so effective birth control is needed while taking this medication. This medication isn’t recommended if you’re pregnant or planning to become pregnant.

Eflornithine (Vaniqa). This cream can slow facial hair growth.

Hair removal. Electrolysis and laser hair removal are two options for removing hair. Electrolysis uses a tiny needle inserted into each hair follicle. The needle sends out a pulse of electric current. The current damages and then destroys the follicle. Laser hair removal is a medical procedure that uses a concentrated beam of light to remove unwanted hair. You might need multiple treatments of electrolysis or laser hair removal. Shaving, plucking or using creams that dissolve unwanted hair may be other options. But these are temporary, and hair may thicken when it grows back.

Acne treatments. Medications, including pills and topical creams or gels, may help improve acne. Talk to your health care provider about options.

To help ease the effects of PCOS, try to:

Stay at a healthy weight. Weight loss can lower insulin and androgen levels. It also may restore ovulation.

Limit carbohydrates. Choose complex carbohydrates, which raise your blood sugar levels more slowly. Complex carbohydrates are found in fruits, vegetables, whole grains and cooked dry beans and peas.

Be active. Exercise helps lower blood sugar levels.