Real Time Continuous Glucose Monitoring System in T2DM With Pregnacy

Inclusion Criteria: * A clear history of type 2 diabetes, or a history of type 2 diabetes diagnosed in early pregnancy * Singleton gestation at 4-26 weeks, with substandard glycemic control (i.e., fasting glucose \> 5.3 mmol/L, and or 1 hour postprandial glucose \> 7.8 mmol/L, and or 2 hours postprandial glucose \> 6.7 mmol/L) after lifestyle intervention ± basal insulin therapy, as assessed by the endocrinology department. Patients who need insulin regimen with basal plus meal or insulin pump regimen. * Patients are willing and committed to establish and follow up in the obstetrics and gynecology departments of Peking University Third Hospital, Haidian District Hospital and Yanqing District Hospital during pregnancy, and are willing to provide information on obstetric examination and perinatal medical records if they are transferred to the hospital for special reasons for follow-up or delivery. * Voluntarily participate in the study, examine and follow up according to this project and sign informed consent. * Able to pass the screening period Adherence evaluation Exclusion Criteria: * Patients with type 1 diabetes, specific type of diabetes or gestational diabetes * Pregnancy with severe comorbidities or diabetic complications for which obstetrics does not recommend continuation of pregnancy, including but not limited to the following: proliferative retinopathy, chronic kidney disease (eGFR less than 60 mL/min/1.73± massive proteinuria), known coronary and cerebrovascular disease, autoimmune system disease and receiving exogenous glucocorticoids or immunosuppressive therapy. * Patients who have been hospitalized for psychiatric treatment within 6 months prior to enrollment or are still on psychiatric medications. * Patients who have received other interventional studies.