What is PCOS? For such an extremely common health problem, not much is known about the causes or treatments of polycystic ovary syndrome, or PCOS. According to the National Office on Women’s Health and leading Chicago egg donation professionals, between 5% and 10% of all women of childbearing age (between 15 and 44) are diagnosed with PCOS; this disorder has equal chances of affecting women at any time after puberty, of any race or background. PCOS and Your Fertility One thing is known for sure about PCOS: it is the leading cause of infertility in women, according to the CDC. This.