A morning fasting blood sugar of 9.0 mmol/L in late pregnancy is serious. The normal value of fasting blood glucose during pregnancy is 5.1mmol/L, fasting blood glucose at 9.0mmol/L is abnormal, consider gestational diabetes or the possibility of diabetes before pregnancy. Gestational diabetes in late pregnancy, the mother in the role of high insulin fetal protein synthesis, lipid-lowering effect decreased, may form a huge child, choose to deliver by way of normal delivery, the fetus may increase the chance of difficult labor. High blood glucose in early pregnancy is likely to lead to fetal malformation, poor glycemic control during pregnancy and large fluctuations in blood glucose are likely to lead to fetal death in utero. Gestational diabetes mellitus in late pregnancy may cause excessive amniotic fluid, which can easily induce contractions causing preterm labor after the pressure in the uterine cavity increases, and premature rupture of membranes can occur with excessive amniotic fluid, which can also induce preterm labor. In late pregnancy, if the blood sugar increases, it is recommended to regulate it through diet and exercise under the guidance of the doctor, and if it fails to return to normal after regulation, it is necessary to apply medication under the guidance of the doctor. Therefore, it is important to monitor your blood sugar during pregnancy and consult a doctor if there is any abnormality.