Prednisone Plus IVIg vs. Prednisone for ITP During Pregnancy

Inclusion Criteria: 1. Age 18-50 years old; 2. Meet the diagnostic criteria for immune thrombocytopenia; 3. Pregnant women with ITP without ITP-specific treatments during pregnancy; 4. Gestational weeks ≥12 weeks; 5. Platelet count \<30×10\^9/L, accompanied with or without bleeding symptoms. 6. Willing and able to sign written informed consent. Exclusion Criteria: 1. Have a known diagnosis of other autoimmune diseases, confirmed medical history or laboratory findings within positive anti-nuclear antibodies (\>1:80), anti-cardiolipin antibodies, lupus anticoagulant factors or direct Coombs' test. 2. Thrombocytopenia caused by pregnancy-specific conditions, such as gestational thrombocytopenia, preeclampsia, the HELLP syndrome and acute fatty liver of pregnancy. 3. Secondary thrombocytopenia such as drug-related thrombocytopenia, vaccine-related thrombocytopenia, lymphoproliferative disorders, severe infection, hepatic cirrhosis and so on. 4. With other underlying diseases that may cause thrombocytopenia, such as: malignant disease, megaloblastic anemia, aplastic anemia, myelodysplasia syndrome, myeloid fibrosis, disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, Hemolytic uremic syndrome, disseminated intravascular coagulation and so on; 5. Current HIV infection or hepatitis B virus or hepatitis C virus infections; 6. With severe heart, kidney, liver or respiratory dysfunction; 7. With the medical history of mental illness; 8. Have allergic reaction to prednisone or IVIg;