Postpartum pericardial effusion may be due to infection, tumor invasion and other reasons, if not treated in time is more dangerous and serious. 1. Infection: Pericardial effusion after delivery may be caused by infection, such as pericardium or myocardium infected with viruses, bacteria, tuberculosis, etc., which leads to pericarditis or myocarditis, resulting in a large amount of pericardial exudate. If the treatment is not timely or thorough, it may cause the symptoms of pericardial adhesion. 2. Tumor invasion: Tumor invasion of the pericardium can cause non-infectious pericardial effusion or blood accumulation. If the treatment is not timely, it may lead to cardiac tamponade, resulting in shock and acute circulatory failure, which may cause death of the patient. Patients with pericardial effusion should be treated promptly to avoid aggravation of the condition.