How Polycystic Ovary Syndrome Is Diagnosed

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Each woman’s experience of polycystic ovary syndrome (PCOS) is unique because no two have the exact same symptoms. This can make diagnosing PCOS difficult. A diagnosis of PCOS can take some time to get to and is based on medical history, physical exam, lab tests, and a review of your symptoms. The diagnostic criteria in use since 2012 require a physical examination, blood tests, and sometimes a transvaginal ultrasound. Excluding other diseases is part of reaching the diagnosis.

Self Checks/At-Home Testing

Your history of symptoms is an important part of the diagnostic procedure. You will be asked about your menstrual periods—how regular they are and the length of time between them—so it's best to come prepared with those answers. This information may help your doctor determine if you are ovulating. Record the details of your menstrual periods in advance and keep an ongoing diary on paper or by using an app.

Also make notes about signs of high androgens or testosterone, including abnormal hair growth (specifically on the face, lower abdomen, back, and chest), acneskin tags, male pattern baldness (if applicable), and acanthosis nigricans (darkened thick skin on the neck, thighs, armpits, or vulva). Note any other unusual symptoms, even if you think they are no big deal.

Because PCOS often runs in families, note whether your mother, sisters, or other close relatives have had PCOS or a history of infertility.

Writing a list of things you want to mention and ask ahead of time can help you remember important points you want to raise in your appointment.

Labs and Tests

Your doctor will want to do a complete physical and pelvic exam to get to the bottom of your issue. Blood work will most likely be taken. Besides testing for hormones like testosterone, estrogen, and follicle stimulating hormone (FSH), your doctor may want to check your body for signs of metabolic complications like high cholesterol, fatty liver, Type 2 diabetes, and insulin resistance. A new hormonal blood test, looking at a woman's AMH (anti-mullerian hormone) is now being used by some physicians as a diagnostic tool as well.

When your blood results come back, you should be able to review them with your doctor and ask questions. If possible, get copies of your blood results sent to you. Many labs now offer free apps you can download to have your blood results sent to your smartphone. 

Oral Glucose Tolerance Test

Women with PCOS are at a much higher risk of developing type 2 diabetes. In fact, according to the Androgen Excess and PCOS Society (AEPCOS), there is a rapid conversion from pre-diabetes to diabetes in those affected. For this reason, AEPCOS recommends that women with PCOS have an oral glucose tolerance test annually if they have impaired levels of glucose, or every other year if glucose levels are normal. This way, diabetes can be detected and treated sooner, helping to prevent complications.

Other Hormone Levels

PCOS is a condition of exclusion, so other conditions that have similar signs and symptoms need to be ruled out before a diagnosis is reached. Your doctor may test your thyroid hormone levels, as thyroid disorders have similar signs and symptoms as PCOS and are common among women with these concerns. 

Endometrial Biopsy

An endometrial biopsy can be performed to determine if your endometrial tissue is in the correct phase or to test for endometrial cancer. This risk of endometrial cancer increases with the number and length of time between missed periods, and the disease is related to hormone imbalances found with PCOS.

The biopsy can be done in your doctor’s office and is relatively painless, although you may experience minimal cramping during the procedure. A small amount of tissue is removed from your uterus through a thin catheter placed through the cervix and into the uterus. This tissue is then analyzed in the context of your cycle and examined for cancer cells.


Transvaginal ultrasound may or not be performed to rule out PCOS. This test may be familiar to you if you've ever been pregnant. A probe is placed inside the vagina, which allows the physician to examine the reproductive organs, look for abnormalities, and measure the thickness of the endometrium.

Your doctor will look for 12 or more small (2 to 9 mm) follicles in each ovary to help confirm a diagnosis. Often times these follicles are called cysts. However, there are many women who have cystic-appearing ovaries without symptoms of hyperandrogenism, and many women who have been diagnosed with PCOS who do not have classically cystic ovaries. Some doctors find the use of a transvaginal ultrasound in adolescents unnecessary, as they may not have the appearance of follicles and may not yet be sexually active.

Differential Diagnoses

When a woman has infrequent, absent, or irregular periods (eight or fewer menstrual cycles in a year), it is a sign that ovulation may not be occurring and could indicate PCOS. It is important to note, though, that women with PCOS can have a monthly menstrual cycle and have PCOS. Coming to a diagnosis involves ruling out other conditions that could be causing your irregular periods, such as thyroid diseasehyperprolactinemiaCushing's syndrome, or congenital adrenal hyperplasia, first.

Menstrual irregularities and the other symptoms of PCOS can point to other conditions. As a result, it's necessary to exclude other conditions in the diagnostic process for PCOS. Ones your doctor will want to rule out include:

To be diagnosed with PCOS, you must meet at least two of the following three criteria:

  1. Irregular or absent periods (fewer than eight menstrual cycles per year)
  2. Blood results or physical signs of hyperandrogenism (high androgens) without another medical cause
  3. The appearance of small follicles on an ultrasound of the ovaries

PCOS Diagnosis Using the Rotterdam Criteria

Under the Rotterdam definition, a woman must meet at least two of three criteria in order to be positively diagnosed with PCOs. These include irregular and/or no ovulation, high androgen levels, and the presence of polycystic ovaries.

The rationale for the Rotterdam criteria can be summarized as follows:

  • Irregular and/or no ovulation is caused by an imbalance of sex hormones, including high levels of testosterone and luteinizing hormone. As a result, some women with PCOS will have a period several times each month, every few months, or not at all. Periods can oftentimes be heavy and accompanied by large clots. Basically, if a woman has eight or fewer menstrual cycles per year, she meets the criteria.
  • High androgen levels are considered key to diagnosing PCOS even though some women with the disorder do not have excess androgen. As such, either serological (blood) or clinical evidence would be accepted. Blood tests with high androgen levels (total and free testosterone, DHEA-sulfate) is enough to satisfy the criteria. In the absence of this, hair loss, acne, and excessive central body hair growth meet the clinical criteria for PCOS.
  • Polycystic ovaries refer to the presence of 12 or more small follicles in each ovary. The follicles sometimes referred to as cysts, resemble a string of pearls. As with androgen levels, women with PCOs do not necessarily have cysts. A transvaginal ultrasound is a primary tool for investigation. The follicles themselves are the result of the hormonal imbalance, not the cause of it.

A Word From Verywell

Being diagnosed with PCOS can be very overwhelming at first. You may want to reach out to the people who care about your, or perhaps a PCOS support group in your area, to have someone to lean on. Following your doctor's advice and learning about your disease is the best way to manage it. Seeking the guidance of other health professionals, such as a registered dietitian nutritionist or therapist, may also be helpful.

While this may all seem like a lot to process, remember that you are not alone. As the most common endocrine disorder among women of childbearing age, there are many women with PCOS who have been through this. The more you know, the more you'll feel control of what comes next.

If you do get diagnosed with PCOS, lifestyle modifications can improve your lab values and reduce your risk for further medical complications. Ask your doctor how he or she plans to treat your PCOS and what you can do. Be sure to ask about other treatment options available, too.

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