The significance of glycated hemoglobin for pregnant women is that: glycated hemoglobin is a monitoring standard to measure blood glucose control, and glycated hemoglobin concentration can effectively reflect the average blood glucose level in the past 8 to 12 weeks. Fasting blood glucose is controlled at 4.5-6.5 mol/L, and two hours after meal blood glucose is controlled at 6.5-8 mol/L. It is recommended to control blood glucose value within 6mmol/L when diabetes is found in pregnancy, and greater than 6.56mmol/L or more is combined diabetes. Glucose cannot be measured alone in gestational diabetes. Monitoring and controlling glycated hemoglobin can prevent the occurrence of giant babies, stillbirths, malformations, and preeclampsia.