Clinical Research Directory

Inclusion Criteria: * Aged \>=18 years; * Pregnancy woman; * With a singleton pregnancy; * Volunteer and receive regular antenatal examinations in the research centers; * Volunteer to sign a written informed consent. Exclusion Criteria: * Concurrent with hypertension, diabetes, liver and kidney diseases, hematonosis and other serious diseases of pre-pregnancy women, including patients requiring long-term medication for primary diseases; * With history of preeclampsia; * Tumor patients concurrent with serious infection requiring long-term drug treatment; * Pregnant women conceiving through in vitro fertilization; * Multiple pregnancies; * Patients with clear indications of medical pregnancy termination during early pregnancy; * Any medical or non-medical conditions deemed inappropriate for study participation according to the investigator.