The goal of this clinical trial is to test effect of dietary management program based on the nudge strategy in gestational diabetes mellitus patients. The main questions it aims to answer is whether the dietary management program is effective for the diet management behavior of gestational diabetes mellitus patients.

Participants will receive a 12 week dietary management program. The intervention group will receive a diet management program based on the nudge strategy, and the control group will receive a routine dietary management program. Researchers will compare two group's glycemic control and pregnancy outcomes and to see if effective for the diet management behavior.

Inclusion criteria

1. Meeting the diagnostic criteria related to GDM by oral glucose tolerance test (OGTT), etc.
2. Singleton pregnancy
3. Age ≥ 18 years
4. Gestational weeks 24-28
5. Informed consent for voluntary participation in this study Exclusion criteria

1.Patients with significant heart, liver, lung and other organ failure and malignancy 2.Previous history of psychiatric disorders or existing psychiatric disorders 3.Diabetes combined with other complications such as gestational hypertension Dropout criteria

1. Lost to the study due to unforeseen circumstances
2. Voluntarily requested to withdraw from the study
3. Did not take the intervention as required by the relevant requirements
4. Condition was unstable and could not continue to cooperate.

Decide not to share participant data from the perspective of protecting participant privacy