Gestational diabetes mellitus(GDM) is one of the most common complications of pregnancy. The incidence of GDM is higher in Asian than in other regions, and GDM can increase the risk of a series of perinatal complications. The investigators has been committed to the early diagnosis of GDM, and several biomarkers in the first trimester and urinary proteomic markers that were associated with GDM have been found. Based on the previous work, the aim of this study was to verify the predictive ability of urinary proteomic markers for GDM that has been found in the previous study of the researchers. This study is a multi-center, prospective, and observational study. Urine samples will be collected twice, at 12 weeks and 24-28 weeks of gestation, respectively.

The eligibility criteria are as follows:

1. singleton pregnant women over 18 years old;
2. gestational age less than 12 weeks;
3. regular follow-up until delivery;
4. able to understand and sign an informed consent.

The exclusion criteria of pregnant women are as follows:

1. with impaired glucose tolerance or diabetes mellitus before pregnancy;
2. severe chronic diseases or infectious diseases (e.g., liver disease, urinary system disease, cardiovascular disease, autoimmune disease, hematological disease, AIDS and other diseases before pregnancy);
3. medications other than vitamins used during pregnancy;
4. inability to understand and follow-up regularly;
5. other conditions judged by the investigators to be inappropriate for participation in the study.

Inclusion Criteria:

• Women of childbearing age who are in early pregnancy(gestational age less than 12 weeks);
• Regular prenatal examination until delivery;
• Older than 18 years old;
• Obtained informed consent from participants and/or their family members.

Exclusion Criteria:

• Twins or multiple pregnancy;
• With impaired glucose tolerance or diabetes mellitus before pregnancy;
• With severe chronic diseases or infectious diseases (e.g., liver disease, urinary system disease, cardiovascular disease, autoimmune disease, hematological disease, AIDS and other diseases before pregnancy);
• Medications other than vitamins used during pregnancy;
• Inability to understand and follow-up regularly;
• Other conditions that were judged by the investigator to be ineligible for participation in the study.

Our study population was pregnant women in early pregnancy who regularly visited the following two medical center: Mudanjiang First People's Hospital, and Mudanjiang Maternal and Child Health Care Hospital. All pregnant women within 12 gestational weeks are eligible for enrollment, and whether entry or not depends on their own preference. There were no requirements for household registration, place of residence, and other identify informations of the enrolled women.