Polycystic ovary syndrome (PCOS) is a health condition that affects the hormone levels in women. It is caused by a variety of complex factors, but the main cause is thought to be an imbalance of hormones, specifically an excess of androgens (male hormones). PCOS can cause a variety of symptoms, including irregular menstrual cycles, excess hair growth, acne, and weight gain. Treatment for PCOS typically involves lifestyle changes, such as diet modification, exercise, and stress management, as well as certain medications.