PCOS - Diagnosis

Diagnosing Polycystic Ovary Syndrome (PCOS) can be surprisingly tricky. Studies suggest that nearly one-third of women with PCOS remain undiagnosed, while many who receive the diagnosis may not actually have it.

This confusion happens because PCOS is a “syndrome of exclusion.” That means doctors must first rule out other conditions that can cause similar symptoms before confirming PCOS.

Step 1 : Ruling Out Other Conditions

Before diagnosing PCOS, doctors check for other endocrine (hormone-related) issues such as:

• Hypothyroidism – an underactive thyroid gland

• Hyperprolactinemia – excessive production of prolactin, the milk hormone

• Nonclassical Congenital Adrenal Hyperplasia (CAH) – a genetic condition affecting hormone production

All of these can look similar to PCOS but are actually different conditions that require different treatments.

Step 2 : Ruling In — The Rotterdam Criteria

Once other conditions are ruled out, PCOS may be diagnosed if two out of three of the following features are present. This is known as the Rotterdam Consensus criteria:

1. Signs of High Androgen Levels (Hyperandrogenism)

Hyperandrogenism means your body is producing too many “male” hormones, such as testosterone.
Doctors look for physical signs like:

• Excess hair growth (on the face, chest, or stomach)

• Thinning hair or baldness on the scalp

• Acne

However, not everyone shows visible signs. For instance, Asian women (Chinese, Japanese, Korean) may have high androgen levels without noticeable hair growth or acne. In such cases, doctors check hormone levels with a blood test.

If you’re taking birth control pills or other hormonal medications, you’ll likely need to stop them for about three months before accurate testing can be done.

2 . Irregular or Absent Ovulation (Oligo- or Anovulation)

This refers to problems with ovulation, which show up as irregular or missing periods.

• Oligoovulation: infrequent ovulation — usually 8 or fewer periods per year

• Anovulation: no ovulation at all

Other menstrual patterns linked to PCOS include :

• Cycles shorter than 21 days

• Cycles longer than 35 days

• Heavy or unpredictable bleeding

3. “Polycystic” Ovaries on Ultrasound

The term “polycystic” is actually misleading — these aren’t true cysts. Instead, it means there are many small, undeveloped follicles or that the ovaries are larger than normal.

An ovary is considered “polycystic” if:

• It has 20 or more developing follicles, or

• The ovary’s volume is greater than 10 ml

However, a person can still be diagnosed with PCOS without polycystic ovaries if the first two criteria (hyperandrogenism and irregular ovulation) are met.