Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) is a clinical and pathological syndrome characterized primarily by excessive intracellular fat accumulation in the liver, excluding alcohol-related and other specific causes. Recent research has identified an association between MASLD and an increased risk of pregnancy-related complications and adverse pregnancy outcomes, including gestational diabetes, preeclampsia, preterm birth, and large-for-gestational-age infants. MASLD in pregnant women poses multiple risks to maternal and infant health. Regular physical exercise during pregnancy has been shown to effectively reduce the incidence of pregnancy complications and adverse outcomes, while also alleviating hepatic steatosis and fibrosis. This study is a randomized controlled trial aimed at exploring the feasibility and effectiveness of online exercise interventions for pregnant women with MASLD, as well as conducting a cost-effectiveness analysis and investigating the underlying physiological mechanisms based on the liver-gut axis. The findings are intended to provide scientific evidence and practical recommendations for managing pregnancy health and intervening in MASLD during pregnancy.

Inclusion Criteria:

1. Singleton pregnancy;
2. Gestational age ≤10-13+6 weeks at enrollment;
3. Age between 20 and 45 years;
4. Patients diagnosed with MASLD;
5. Signed informed consent.

Exclusion Criteria:

1. Cervical length ≤ 25 mm;
2. History of threatened abortion;
3. Exercise contraindications or doctor advice not to exercise during pregnancy;
4. Current or previous use of drugs that affect body weight (such as hormones);
5. Patients with chronic hepatitis virus or other chronic liver diseases, excluding MASLD;
6. Non-natural conception or infertility treatment;
7. Any previous medication for hypertension, diabetes, heart disease, kidney disease, systemic lupus erythematosus, thyroid disease or mental illness;
8. Participating in other pregnancy intervention research projects.