Polycystic ovarian syndrome is frequently undiagnosed, with one in ten women having PCOS but up to 50% of women with the disorder going undiagnosed and untreated. Even the name of the disease is a misnomer, causing more confusion regarding an already confusing disorder. So, what is PCOS? Polycystic ovarian syndrome is a hormonal disorder common among women of reproductive age. People with the disease may have infrequent or prolonged menstrual periods or excess androgen, or m