In women of reproductive age, most ovaries contain tens of thousands of follicles from which an egg could be ovulated.
But only some of those
follicles are big enough to be seen with ultrasound at any one time. They are called antral follicles. The normal ovary contains about 3-5
Some ovaries have more than this number of follicles and if the number is >12, in the absence of any hormonal stimulation they are called polycystic.
About 15% of all women have polycystic ovaries. They are so common that one would have to consider them to be a variant of normal.
They are of interest to us because women with polycystic ovaries have a tendency to ovulate irregularly and therefore have irregular periods, or no periods at all for a long time.
Polycystic ovaries can also be associated with other hormonal problems and when they are, doctors call it the “polycystic ovarian syndrome”. Many women have polycystic looking ovaries however, and they do not have the syndrome.
Trans-vaginal image of a polycystic ovary. This patient did not
have polycystic ovarian syndrome. She had regular periods and
no hormonal disturbance.
Trans-vaginal image of a polycystic ovary. This patient did have
polycystic ovarian syndrome. She had irregular periods, acne
and was having trouble getting pregnant