Biliary atresia cannot be detected in the early stages of pregnancy. If biliary abnormalities are detected during 4D ultrasound in the middle or late stages of pregnancy, regular follow-ups are needed, and the possibility of detecting biliary atresia in a fetus with a more serious condition cannot be ruled out. The presence of biliary atresia in the fetus needs to be judged according to the period of pregnancy and the specific condition of the fetus. Pregnant women need to develop good habits of living, eating and living, a good state of mind, and do a good job of all pregnancy tests. Especially the four-dimensional ultrasound examination is particularly important, which can clearly determine whether the fetus has malformations, so as to facilitate timely detection and timely treatment, which can minimize the birth of malformed babies and reduce the burden on society and the financial burden on individual families.