Diagnose PCOS with a Transvaginal Ultrasound

Diagnostic Criteria for Diagnosing Polycystic Ovarian Syndrome (PCOS)

Female physiotherapist using ultrasound machine on client in clinic examination room
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Transvaginal ultrasound is one of the main tools a physician has when it comes to diagnosing polycystic ovary syndrome (PCOS). The images found on the ultrasound, in conjunction with the results of blood tests and a thorough patient history and physical, are used to diagnose this syndrome.

Diagnosing Polycystic Ovary Syndrome (PCOS)

Characterized by high levels of androgens, (male hormones like testosterone), polycystic ovary syndrome (PCOS) is an imbalance of sex hormones.

Since these hormones are involved in the regulation of bodily processes ranging from reproduction to metabolism, the condition can lead to a wide variety of signs and symptoms of PCOS.

PCOS Exclusions

The first step when evaluating your symptoms, exam and laboratory findings is to exclude other disorders which might cause these findings. These conditions (which may appear similar to PCOS but are different) include:

Diagnostic Criteria for PCOS (The Rotterdam Criteria)

The current diagnostic criteria for women with PCOS state that a woman has PCOS if she has two of the following three criteria (with the exclusion of all other criteria):

1. Absent or irregular menstrual cycles (eight or fewer periods in one year). Since only two of these three criteria need to be met, there are some women who will meet the criteria for a diagnosis of PCOS despite having regular monthly menstrual cycles.

2. High androgens on blood work or signs of high androgens in the body such as acne, excessive hair growth (hirsutism), or male pattern hair loss (androgenic alopecia).

Blood tests often reveal elevated testosterone and free testosterone levels as well as dehydroepiandrosterone sulfate (DHEAS) levels.

3. The presence of follicles—commonly referred to as cysts erroneously—on an ultrasound (see clarification below). Some criteria define PCOS as having 12 or more small follicles (that are between two and nine mm in diameter) in both ovaries. However, in the United States, physicians do not typically rely solely on that definition in order to make a diagnosis. There are many women who have cystic ovaries without symptoms of hyperandrogenism, and many women who have been diagnosed with PCOS who do not have classically "cystic" ovaries. Recent studies suggest that measuring anti-Mullerian hormone levels may be a useful substitute for transvaginal ultrasound in some cases for the diagnosis of PCOS.

If Your Diagnosis is Uncertain

If you are uncertain about your diagnosis of PCOS (or lack of one), it can’t hurt to get a second opinion. Endocrinologists and reproductive endocrinologists are medical specialists with additional training in evaluating and treating hormonal disorders. Check out the American Society for Reproductive Medicine or the Androgen Excess and PCOS Society for a local recommendation.

How Is a Transvaginal Ultrasound Performed?

A transvaginal ultrasound can be performed in a doctor's office. For the procedure, you may be asked to drink up to 42 ounces of fluid before your test to fill your bladder, making it easier to see your ovaries. A lubricated ultrasound probe is placed inside the vagina, which transmits an image of the internal organs onto a screen. An ultrasound technician then measures and takes pictures of your ovaries and shares them with your doctor. 

Does Transvaginal Ultrasound Hurt?

Some women may experience very mild discomfort while the technician pushes down during the ultrasound (remember, full bladder!), depending on the ease in which the sonographer can locate the internal reproductive organs.

What Is the Doctor Looking for on the Ultrasound?

The sonographer will examine your uterus, cervix, and uterus. The number of follicles on your ovary will be counted to yield what is known as an antral follicle count (AFC).

What Are Antral Follicles?

Antral follicles are resting follicles that are found in the ovary at the beginning of each menstrual cycle. They are approximately two to nine mm in size (less than half an inch). A high antral follicle count indicates that a woman has a large number of eggs remaining in her ovary and, in some cases, PCOS.

Cysts vs. Follicles in PCOS

Both cysts and follicles are more common in women with PCOS than those without the condition. Many confuse cysts with follicles.

Despite its name, women with PCOS don't typically produce cysts, but rather follicles are used as part of the diagnostic criteria (see below). A name change for PCOS has been proposed to clear up confusion and properly educate health professionals and consumers. 

Women with PCOS tend to produce follicles, which are small collections of fluid in the ovary and are the result, not the cause of, the imbalance of sex hormones. Each month, a woman produces follicles that mature and get released from the ovaries in order to be fertilized. Because of the hormone imbalance, these follicles don't mature and don't get released by the ovaries, which often leads to infertility. Learn more about the causes and the root of the problem with PCOS.

Bottom Line on Diagnosing PCOS With Transvaginal Ultrasound

The diagnosis of PCOS can be time-consuming and frustrating. Other conditions which can cause similar symptoms need to be ruled out first, and then symptoms such as menstrual abnormalities and evidence of androgen excess are evaluated. Transvaginal ultrasound can provide important information about follicles (as opposed to cysts which has led to much confusion over the years.) The measurement of the anti-Mullerian hormone may provide a substitute for ultrasound in some circumstances.

Once a diagnosis is made, the treatment options for PCOS can be reviewed in order to help you cope with the many annoying (and sometimes serious) consequences of the condition.

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