The glucose tolerance test is usually done in the 6th to 7th month of pregnancy, and can be done as early as 20 weeks for pregnant women with high risk factors for gestational diabetes.
Glucose tolerance test can further diagnose whether gestational diabetes occurs in pregnant women and is an important screening program for gestational diabetes.
Generally, pregnant women who do not have high risk factors for gestational diabetes can have a glucose tolerance test in the sixth to seventh month of pregnancy, i.e., 24 to 28 weeks.
Pregnant women with risk factors for gestational diabetes, such as body mass index suggestive of obesity, family history of diabetes, pre-pregnancy diabetes or abnormal glucose tolerance, and previous history of gestational diabetes, can advance the glucose tolerance test to 20 weeks for early diagnosis and intervention.