_{Polycystic ovary syndrome (PCOS)}

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Polycystic ovaries contain a large number of harmless cysts that are no bigger than 8mm each. Normal ovaries have only about half this number of cysts.

The cysts are under-developed follicles which contain eggs that haven't developed properly. Often in PCOS, these follicles are unable to release an egg, meaning ovulation doesn't take place.

Many women have polycystic ovaries without having the syndrome (without the symptoms). Some women have the syndrome, but have normal-looking ovaries on ultrasound. From the NHS Choices website

Visit their site to read and learn more about PCOS NHS Choices

Other sources:

• Polycystic ovary syndrome (PCOS) fact sheet
  Verity
  Polycystic ovary syndrome (PCOS): what it means for your long-term health - information for you
  MayoClinic