A 75g glucose tolerance test during pregnancy with a fasting blood glucose value of 7.51mmol/L is higher than the standard range, while a blood glucose value of 7.51mmol/L 1 hour or 2 hours after taking sugar is within the normal range. Glucose tolerance test is a commonly used laboratory method to diagnose the presence of gestational diabetes mellitus. It measures the fasting and 1-hour and 2-hour blood glucose values after taking sugar, and if they are lower than 5.15mmol/L, 10.05mmol/L and 8.5mmol/L respectively, then they are normal. Gestational diabetes can be diagnosed as long as the blood glucose value at one of these time points meets or exceeds this standard. Glucose tolerance test is a commonly used laboratory method to diagnose the presence of gestational diabetes mellitus, and fasting blood glucose is usually measured at 24-28 weeks of pregnancy. In case of abnormal results, an obstetrician should be consulted and dietary instructions should be given by an obstetrician or dietitian, and fasting and postprandial blood glucose levels should be monitored on a regular basis.