Inclusion Criteria:  The patient was older than 18 years old and had not been diagnosed with diabetes before pregnancy. A 75-gram glucose load examination was performed during 24-28 weeks of gestation：GDM should be diagnosed at any time in pregnancy if one or more of the listed criteria are met following a 75-gram glucose load: fasting PG ≥5.1 mmol/l; 1-hour PG ≥10.0mmol/l; 2-hour PG 8.5-11.0 mmol/l. If the patient is younger than 18 years old, consent from parents or guardians is required; Inclusion objects in line with the above sample sources; Signed the informed consent;  Exclusion Criteria:  Refuse to sign the informed consent Severe mental symptoms, unable to cooperate with blood collection