Glucose tolerance test is a method to measure the presence of diabetes mellitus or gestational diabetes. Sometimes patients with polycystic ovary syndrome also have abnormal glucose metabolism and need to undergo glucose tolerance test. Glucose tolerance test mainly involves giving the patient a one-time dose of 75g of glucose, and measuring the blood glucose value and insulin level before, one hour after, and two hours after taking the glucose. If the blood glucose in the body rises higher, it means that the response to high glucose in the body is decreased and there is an underlying irregularity in the function of the pancreas. Therefore, abnormal glucose tolerance often indicates a risk of developing diabetes or gestational diabetes.