Polycystic ovaries (PCO) refers to one or both ovaries being bigger than normal and/or having a high number of small egg-containing ‘antral follicles. This is determined with an ultrasound scan of the ovaries. PCOS or Polycystic Ovarian Syndrome needs 2 out of 3 of: 1. Irregular cycles 2. Clinical or blood test signs of too much male hormones – acne, unwanted hair growth or oily skin and 3. PCO. Up to 20% of women have PCO, about 8-10% have PCOS.