PCOS (Polycystic ovarian syndrome) is a disease that effects one in four women. It's a problem in which a woman's hormones are out of balance. It can cause problems with your periods and make it difficult to get pregnant. PCOS also may cause unwanted changes in the way you look. It can ungovernable you facial hair, hair loss and weight gain mostly to the upper body. If it isn't treated, over time it can lead to serious health problems, such as diabetes and heart disease.