The test of drinking sugar water is generally referred to as glucose tolerance, which is a test used to check whether a pregnant woman has combined gestational diabetes. Glucose tolerance test is usually done between 25-27 weeks of pregnancy. Before the test, the fasting blood glucose should be measured firstly, and then 75g of glucose solution should be drunk, and then the blood glucose should be measured once in 1 or 2 hours. If the fasting blood glucose exceeds 5.1mmol/L, 1 hour after taking 75g of glucose, the blood glucose exceeds 10mmol/L, or the blood glucose exceeds 8mmol/L after 2 hours, it means that the pregnant woman may have combined gestational diabetes. If the data is within the normal range, it is healthy. Glucose tolerance test is a mandatory test for women in the middle of pregnancy. If a woman suffers from gestational diabetes, it may affect the development of fetal lungs, while high blood glucose may also lead to macrosomia, or in severe cases, intrauterine growth restriction of the fetus. Therefore, gestational diabetes patients should first control their diet, try to avoid eating foods with high sugar content, and if necessary, use insulin to control blood sugar under the guidance of a doctor.