When a fetus is detected with pericardial effusion during pregnancy, the management of pericardial effusion requires a comprehensive assessment and dynamic observation in conjunction with the volume and etiology of the effusion before deciding on the next step in management. A visit to the prenatal diagnostic unit is recommended. A. Small amount of pericardial effusion: If the amount of pericardial effusion is less than 2mm, it is generally considered physiological and does not require special treatment, only regular obstetric examination and observation of dynamic changes. If the amount of pericardial effusion is more than 2mm, there may be pathological problems and further investigation of the cause is needed. 1. Detailed consultation: including whether there is cold, fever, rash, enlarged lymph nodes, abdominal pain, vaginal bleeding during pregnancy, as well as past maternal history, disease history, genetic history, and whether there are complications during pregnancy. What items were done in the previous chromosome screening program; 2. Level 4 ultrasound: systematic screening of various fetal organs, as well as to see if there is fetal pulmonary edema, pleural effusion, peritoneal effusion, skin edema, etc.; 3. Cardiac ultrasound: screening of the fetus for structural heart abnormalities; 4. Viral screening: including rubella virus, cytomegalovirus, and toxoplasmosis, etc., to detect whether pericardial effusion is caused by viral infection. Based on the medical history and ultrasound results, the pregnant woman will be evaluated for prenatal diagnostic indications. Amniocentesis or cord blood puncture can be performed for fetal karyotype, chromosomal microdeletion microrepeat syndrome, viral nucleic acid, etc. It is recommended to review the ultrasound at about 2 weeks to observe the dynamic changes and to see if the effusion has further worsened. If the condition of the fetus does not worsen and the baby can be born successfully, it is recommended that the mother should have regular maternity checkups and follow the doctor’s instructions for targeted treatment. If the effusion is too large, or even combined with fetal developmental malformations, it is recommended to terminate the pregnancy under the guidance of the doctor.