Gut microbiota is instrumental in the microbial and metabolic network of pregnant women, and is potentially related with gestational diabetes. Perinatal probiotic intervention contributes to improved glucose regulation during pregnancy. Our randomized, double-centered, placebo-controlled study is planned to recruit 334 pregnant women who is in high risk for gestational diabetes. They will be assumed randomly probiotic powder per day or placebo from 12-16th gestational weeks until Oral Glucose Tolerance Test (OGTT) at 24-28th gestational weeks. Perinatal outcomes about neonatal weight will be registered.

Inclusion Criteria:

• Pregnant women who meet the high-risk indicators for GDM and agree to participate in this study.

  1. included between 12-16 gestational weeks
  2. A woman was considered high risk when her pre-pregnancy BMI ≥ 24 kg/m^2, having family history of diabetes (type 1 or 2), GDM or PCOS (polycystic ovary syndrome) history, history of delivering macrosomia or stillbirth, or glucose in urine (+)

Exclusion Criteria:

1. Taking probiotics or prebiotics within the past month
2. Have a history of allergies to the drug components or similar drugs in this study
3. Having long-term smoking or drinking habits
4. Type 1 or type 2 diabetes patients with definite diagnosis before pregnancy
5. Diseases in other important organs such as heart, liver, and kidney
6. with clear digestive system diseases
7. Multiple pregnancy
8. with mental or cognitive impairments who are unable to complete this study

The random number table is compiled by the investigator who is specially responsible for grouping and saved. The investigator packaged and coded drugs according to random number table, and recorded. The packaged and numbered drugs are stored in the enrollment office.

When the participants meet the inclusion criteria by care providers (doctors), the enrollment office generates a random number for each subject. The participants received the package of drugs according to their random number, and the random number was recorded in the record book.

If there are adverse events or the subjects request to withdraw from the trial, the investigator should uncover the blind.