Early Prediction of Gestational Diabetes in High-risk Women Based on Breath Metabolomics

Eligibility Criteria * 18-55 years old * 11-14 weeks of pregnancy * at least one risk factor for GDM * signed a written informed consent Exclusion Criteria: * Diabetes mellitus or abnormal glucose metabolism before pregnancy * Hyperemesis gravidarum (urine ketone positive)) * Thyroid dysfunction * Asthmatic patients * Hypertensive diseases that are difficult to control * Severe hepatic and renal insufficiency or severe electrolyte disturbance * Malignant tumor * Acute inflammation * lung disease * Patients with gastritis, duodenum and other digestive system diseases * Those with upper respiratory or oral problems who cannot cooperate with expiratory collection * smoker