Gallbladder not visible in 4D is mostly found in pregnancy examination, which is considered to be related to fetal position factor, fetal malformation, congenital biliary atresia and so on. 1. Fetal position factor: when pregnant women do four-dimensional ultrasound examination, the fetus does not cooperate with the examination or the fetal position is not appropriate, will have a certain impact on the examination results, thus inducing four-dimensional ultrasound can not see the gallbladder phenomenon. 2. Fetal malformation: Fetal malformation is related to chromosomal abnormality, genetic abnormality, exposure to chemical substances or radiation. When the fetus is malformed, the gallbladder may not be seen on 4D ultrasound, and other examinations may also reveal spina bifida, hydrocephalus, cleft lip and palate, and so on. 3. Congenital biliary atresia: Diseases can also cause some pregnant women to do four-dimensional ultrasound examination can not see the fetal gallbladder. The cause of congenital biliary atresia is still unclear, and may be related to infection, heredity, and interference with the biliary tract during fetal development. It is recommended that those who cannot see the gallbladder in the 4D ultrasound examination should repeat the examination after a period of time, and if necessary, undergo amniocentesis and other tests in order to clarify whether the development of the fetus is abnormal or not.