Glucose screening, or screening for gestational diabetes, is done through the glucose tolerance test (OGTT). The normal range of glucose tolerance during pregnancy is less than 5.6 mmol/L for fasting, less than 10.3 mmol/L for 1 hour after oral glucose, and less than 8.6 mmol/L for 2 hours after oral glucose. If the results of all three tests are within the normal range, the glucose tolerance is normal. If any of the above three tests meet or exceed the criteria, then gestational diabetes is diagnosed. High glucose tolerance in pregnancy can have a significant impact both on the pregnant woman and on the fetus. Not only does gestational diabetes have the potential to cause hypertonic coma and ketoacidosis in pregnant women. It may also cause excessive fetal growth, leading to the emergence of a giant baby, or the fetus may not absorb sufficient nutrients and cause malnutrition, delayed fetal lung development, and intrauterine hypoxia in late pregnancy. Therefore, it is important for pregnant women to pay attention to gestational diabetes screening. If a pregnant woman is diagnosed with gestational diabetes, she should immediately take diet and exercise intervention, and monitor fasting blood glucose and two-hour postprandial blood glucose, and if the blood glucose is still abnormal, she should seek medical attention and use insulin for blood glucose control under the guidance of a doctor.