A polycystic ovary is an ovary that shows many small follicles or increased ovarian volume on ultrasound.
What this appearance means
A polycystic ovarian appearance means ultrasound finds many small follicles in the ovary, or an ovarian volume larger than usual. Despite the name, these follicles are not harmful cysts. They are immature eggs whose development stalls when ovulation does not happen regularly. When eggs are not released, these follicles build up and look numerous on the scan. This is why the name of the condition is often misunderstood, since people picture large cysts when what is seen is really small, ordinary follicles. The link between ovulation and this appearance is explained on the what is PCOS page.
How it relates to the PCOS criteria
A polycystic ovarian appearance is one of the three Rotterdam criteria for PCOS, alongside irregular periods and signs of high androgens. This means a polycystic-looking ovary is not the only marker, and it is not enough on its own to confirm the condition. A doctor reads it together with your cycle pattern and hormone results before drawing any conclusion. Likewise, some people have this appearance yet do not meet the other PCOS criteria. The hormonal background involved is on the hormones page.
Why it does not confirm PCOS on its own
A polycystic appearance on its own does not confirm PCOS, because it can also show up in healthy young women with no other symptoms. At certain ages this appearance is fairly common and does not necessarily signal a problem. That is why a single scan should not be read in isolation. Other features, such as insulin resistance, also need to be assessed, and these are discussed on the insulin resistance page.
When to talk to a doctor
If your scan shows a polycystic ovarian appearance, a doctor can explain what it means in the context of your other symptoms and test results. This finding alone does not need to cause worry without a full assessment, because it is only one part of a larger picture. A doctor combines it with your cycle pattern, symptoms, and blood test results before drawing any conclusion. Any decision about further assessment or care should be discussed with a doctor or pharmacist.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.