Glucose screening, or screening for gestational diabetes, is done through a glucose tolerance test (OGTT). The normal range for glucose tolerance during pregnancy is: fasting blood glucose less than 5.6 mmol/L, one hour after oral glucose less than 10.3 mmol/L, and two hours after oral glucose less than 8.6 mmol/L. If the results of all three tests are within the normal range, then the glucose tolerance is normal. If any of these three tests are at or above the standard, then gestational diabetes is diagnosed. High glucose tolerance in pregnancy can have a significant impact on both the pregnant woman and the fetus. Gestational diabetes not only has the potential to cause hyperosmolar coma and ketoacidosis in pregnant women. It may also cause excessive fetal development, leading to the emergence of giant babies, or the fetus can not absorb sufficient nutrients and cause malnutrition, delayed development of fetal lungs, intrauterine hypoxia in late pregnancy and so on. Therefore, pregnant women should pay attention to the importance of screening for gestational diabetes on time. Pregnant women diagnosed with gestational diabetes should immediately take dietary modifications, as well as exercise interventions, and monitor fasting blood glucose and two-hour postprandial blood glucose, and those whose blood glucose is still abnormal should consult a doctor in a timely manner, and use insulin under the guidance of the doctor for blood glucose control.