Down screening is Down’s syndrome screening and glucose tolerance is glucose tolerance test. These are two different tests during pregnancy, and they differ in the time, method and purpose of the test. 1. Screening time: Down’s screening is usually performed at 15-20 weeks of pregnancy, and glucose tolerance test is usually performed at 25-28 weeks. 2. Screening method: Down’s syndrome screening is to draw blood from a vein of the pregnant woman for examination, and fasting is not required before the blood is drawn. Glucose tolerance test needs to go to the hospital on an empty stomach, and blood is drawn once on an empty stomach, and then again 1 hour and 2 hours after taking 75g of glucose orally to check the blood glucose value of the three blood draws. 3. Purpose of the test: Down’s syndrome screening is mainly a screening tool to check whether the fetus has trisomy 21, trisomy 18 and open neural tube defects. Glucose tolerance test is mainly to check whether the pregnant woman has gestational diabetes. It is important for pregnant women to do their labor and delivery tests at the prescribed time and seek medical attention if there is any abnormality.