The commonality between PCO and PCOS are the cystic follicles on the ovaries. These do disappear, only to be replaced by further cystic follicles. Some of these follicles are dormant, other release hormones, another may contain an egg.
PCO is basically the cystic follicles without any of the other symptoms usually associated with PCOS (these can include hirsuitism, irregular periods, irregular or non existant ovulation, adult onset acne to name but some).
Docs are not fully sure what the causes of PCOS are. There is no for PCO/S but it can be managed.
However, PCOS is a very individualistic disorder and can affect each woman with it very differently.
I was diagnosed with PCOS based on my bloodwork and irregular periods. I received treatment and am now a parent/
You may find verity's website helpful www.verity-pcos.org.uk
Any other questions just ask