The cause of biliary atresia is not fully understood. Currently, theories related to the cause of atresia include embryonic developmental abnormalities, viral infections, and other etiologic factors. 1. Abnormal embryonic development: In the past, scholars believed that the bile ducts go through the filling, vacuolar, and atresia stages during embryonic development. If the development of the bile duct stops during the vacuolar stage, biliary atresia can occur. 2. Viral infection: now more and more scholars believe that some viruses are infected during fetal development, leading to biliary atresia. Common viruses include cytomegalovirus, rotavirus, human papillomavirus and so on. 3. Other causes: besides the above causes, scholars also suggest that biliary atresia is related to heredity, gene mutation, autoimmunity, embryonic ischemia, toxin poisoning and other factors. For patients diagnosed with biliary atresia, they should immediately go to the relevant departments of regular hospitals for treatment under the guidance of specialized physicians, so as to avoid delaying the condition and causing adverse consequences.