The malformations that are ruled out in the second 4D examination include surface malformations, visceral malformations, and cephalo-facial malformations. Four-dimensional ultrasound is a kind of ultrasound examination, which is able to carry out three-dimensional imaging for the head and face of the fetus, and can clearly display the eyes, nose, mouth and jaw, etc., which can help specialists to directly make relevant judgments on the congenital malformations of the fetus, which generally include surface malformations, visceral malformations and cephalo-facial malformations. In addition, 4D ultrasound examination can also add time dimension parameter on the basis of function, and can observe the dynamic activity image of the fetus in real time, and can observe whether the fetus has congenital heart disease, hydatidiform fetus and cleft lip and palate, as well as polydactyly and malformation of the outer ear and so on. Therefore, four-dimensional color ultrasound examination is more important, it is recommended that patients need to actively cooperate with the examination.