Shanghai Clinical Cohort of Hyperglycemia in Pregnancy

Inclusion Criteria: * Pregnant individuals who provide written informed consent * At enrollment, meet one of the following: 1\. Gestational diabetes mellitus (GDM) diagnosed by a 75-g oral glucose tolerance test (OGTT) using Chinese Diabetes Society (CDS) 2024 thresholds (any one of: fasting plasma glucose ≥5.1 mmol/L, 1-h ≥10.0 mmol/L, or 2-h ≥8.5 mmol/L); or 2. Pre-gestational diabetes (type 1 or type 2) documented prior to pregnancy or meeting diabetes criteria at the first prenatal visit (e.g., fasting ≥7.0 mmol/L, 2-h OGTT ≥11.1 mmol/L, or HbA1c ≥6.5%); or 3. At high risk for GDM, defined a priori as ≥1 of the following: prior GDM; prior macrosomic infant (≥4,000 g); pre-pregnancy BMI ≥24 kg/m²; age ≥45 years; high-density lipoprotein cholesterol \<1 mmol/L, and/or triglyceride levels \>2.8 mmol/L; first-degree family history of diabetes; polycystic ovary syndrome (PCOS); history of coronary heart disease; chronic hypertension and repeated positive fasting urinary glucose in early pregnancy * Age ≥18 years at the time of consent * Willing and able to attend postpartum assessments (OGTT at 6 weeks, 12 months, and annually thereafter), with planned follow-up ≥3 years Exclusion Criteria: * Current or history of illicit drug use or substance abuse * Presence of an active infectious disease, including but not limited to: viral hepatitis, sexually transmitted infections or tuberculosis * Any other condition which, in the judgment of the investigator, would make the subject unsuitable for enrollment in the study