Glucose tolerance test is necessary during pregnancy to diagnose the presence of diabetes, etc. based on the results, so it is recommended to perform glucose tolerance test during pregnancy. The incidence of gestational diabetes is increasing significantly. Glucose tolerance test can detect blood glucose in pregnant women and help to detect gestational diabetes for treatment. Glucose tolerance test is generally used oral glucose tolerance test, the judgment standard is fasting and 1 hour after taking sugar, 2 hours of blood glucose value is lower than 5.1mmol / L, 10.0mmol / L, 8.5mmol / L, respectively, any one of these three items are elevated, can be diagnosed as gestational diabetes mellitus. Gestational diabetes mellitus, if not detected and treated in a timely manner, poor glycemic control and poor control of the condition can have immediate and long-term adverse effects on the pregnant woman and the fetus, so it is recommended that pregnant women go for glucose tolerance tests.