Is There a Difference Between PCO and PCOS?

Medically Reviewed on 9/19/2022
Is There a Difference Between PCO and PCOS
Here is everything you need to know about the differences between PCO and PCOS

Although polycystic ovaries (PCO) and polycystic ovary syndrome (PCOS) sound similar, the two conditions are not the same. 

PCO occurs when there is an increased number of small cysts in the ovaries. PCOS is an endocrine disorder that causes women to produce excess androgens (male hormones).

Here is everything you need to know about the differences between PCO and PCOS.

What is PCO vs. PCOS?


A polycystic ovary (PCO) is a large ovary with 12 or more follicles instead of a single dominant follicle. These cysts are typically harmless and do not cause symptoms in most women. 

PCOs are commonly detected during an ultrasound or other forms of pelvic imaging.


Polycystic ovary syndrome (PCOS) is a condition caused by hormonal imbalance. It is associated with insulin resistance and the release of male sex hormones that cause disturbances in ovulation.

What are the differences between PCO and PCOS?

PCO is more common than PCOS

PCO is found in 19%-33% of women with or without symptoms. PCOS affects 5%-10% of women between 15 and 44 years. 

PCO is not a disease, whereas PCOS is a metabolic condition

PCO refers to a large ovary with 12 or more follicles that measure 2 to 9 mm. Women with PCOS may have PCO along with these symptoms:

  • Long menstrual cycles of more than 35 days or complete absence of menstruation
  • Increased male hormones
  • Less ovulation

PCOS can lead to other complications, whereas PCO doesn’t cause many

Some of the complications associated with PCOS include:

PCO typically doesn’t cause any complications as opposed to PCOS.

Pregnancy may be difficult with PCOS, but women with PCOs can still get pregnant

Women with PCOs can get pregnant, but conception becomes difficult with PCOS. Moreover, women with PCOS may have a higher miscarriage rate than those with PCOs.

Ovulation may be difficult with PCOS compared to PCO

As PCOS is associated with hormonal imbalance, insulin resistance, and excess androgen secretion from the ovaries, ovulation becomes difficult with this condition. However, PCO doesn’t cause any hormonal imbalances, thereby leading to frequent ovulation.

PCO may or may not cause symptoms, whereas PCOS can cause various symptoms

PCOS can cause symptoms such as acne, infertility, infrequent menstrual periods, and excess hair growth. PCO may be accidentally identified during an ultrasound because most women do not exhibit any symptoms.


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Medically Reviewed on 9/19/2022
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Polycystic Ovary Versus Polycystic Ovary Syndrome:

Polycystic Ovary Syndrome (PCOS):