Patients with polycystic ovary syndrome are associated with abnormal menstruation and an increased number of follicles on ultrasound. However, only about 70% of the patients with polycystic ovary syndrome have insulin resistance, which is the pathological basis of type 2 diabetes mellitus. In patients with insulin resistance, the presence of abnormal factors can affect the development of follicles, so that patients with polycystic ovary syndrome do not have follicles to develop and the follicles do not grow and ovulation does not occur, which eventually leads to infertility. Therefore, patients with insulin-resistant polycystic ovary syndrome must be treated to prevent the occurrence of type 2 diabetes and to enable them to conceive successfully and achieve fertility. Not all patients with polycystic ovary syndrome have insulin resistance. Insulin resistance is often seen in patients with polycystic ovary syndrome with obesity.