Generally if only fasting blood glucose is looked at, 1 time drawing before meal is fine. If fasting blood glucose is at the critical value, it is necessary to do glucose tolerance test, such as half hour, 1 hour or 2 hours after meal to draw blood for test respectively. If blood glucose is done at the 1st blood collection and blood glucose will appear 5.1mmol/L or 5.1mmol/L a little too much, it is recommended to do a glucose tolerance test. The glucose tolerance test requires the pregnant woman to take a specific sugar, to have the blood drawn half an hour after taking the sugar in a very short time, and to wait for 1 hour or 2 hours after the blood is drawn, to monitor the blood glucose at these times, respectively, to see how the glucose tolerance test is going, and to determine whether she has gestational combined diabetes according to the glucose tolerance curve.