From the Article 11 Signs You Might Have PCOS And Not Even Know It on Bustle.com:
As is the case with many health concerns, how to know if you polycystic ovary syndrome (PCOS) can be difficult to tell on your own, unless you know exactly what to look for. And even then, signs of this hormonal and reproductive disorder can be easy to miss. In fact, “half of the 10,000,000 women who have it are unaware of it,” Sinem Karipcin, MD, a fertility specialist at Conceptions Florida, tells Bustle.
Partially to blame are the easy-to-miss symptoms, as well as the fact PCOS can be difficult for doctors to diagnose, due to all the factors involved.