It is possible to have a glucose tolerance test at 30 weeks of pregnancy. The best time for the glucose tolerance test is between 24-28 weeks, but this time is not absolute. If the glucose tolerance can be done beyond this time, the results are still valid for checking whether the pregnant woman’s blood sugar is too high. Therefore, it is important for pregnant women to remember to go for the glucose tolerance test even if they are overdue. If a pregnant woman has a family history of diabetes or has high blood sugar in the past, and if she is obese or eats high-calorie food frequently, it is recommended that she should have a glucose tolerance test done early so that abnormalities in blood sugar can be detected and treated early. In addition, because glucose tolerance draws venous blood to test the amount of glucose in the blood, the sugar contained in food can increase the blood glucose concentration and lead to abnormal test results, so it is important to fast and abstain from food and water after 8 p.m. the night before until 3 blood draws are completed.