What is polycystic ovary syndrome? Polycystic ovary syndrome is a common gynecological disease. It is caused by the failure of the follicles in the ovaries to develop normally, causing the ovaries to become swollen, and at the same time, the body\’s secretions are imbalanced, leading to infertility, menstrual irregularities and other problems. Its main symptoms include irregular menstruation, abdominal pain, multiple follicles and excessive menstruation.