The reference values for glucose measurement in pregnant women are fasting, 1 hour and 2 hours after taking sugar, the blood glucose value is lower than 5.1mmol/L, 10.0mmol/L, 8.5mmol/L respectively, and the elevation of any of these three items can be diagnosed as gestational diabetes mellitus. During pregnancy, changes occur in the organs of the pregnant woman’s body and her blood glucose level can also change. During pregnancy, it is important to keep glucose within the normal range to protect the health of the mother and child. The reference value when performing the 75g glucose tolerance test is that the blood glucose values of fasting and 1 hour and 2 hours after taking glucose are lower than 5.1mmol/L, 10.0mmol/L and 8.5mmol/L respectively. Elevated blood glucose during pregnancy can be very harmful to the pregnant woman’s own body, the fetus, and the newborn. Pregnant women may develop embryonic abnormalities, microangiopathy, and excess amniotic fluid. The fetus may develop malformations, miscarriage or preterm labor, and intrauterine distress. Newborns may develop respiratory distress syndrome, hypoglycemia, and macrosomia. Pregnant women who are found to have high blood glucose during labor and delivery need to intervene aggressively to reduce the incidence of adverse pregnancy outcomes.