Four-dimensional, or four-dimensional ultrasound, is routinely the best to do four-dimensional ultrasound examination. Through four-dimensional ultrasound can be more clearly observed fetal brain, heart, kidneys, intestines, liver and other parts of the malformation, as well as fetal body surface, limbs have no deformities, is to rule out fetal malformation of a kind of examination program. Clinically, 2D and 3D ultrasound as well as other items are generally needed during pregnancy to rule out fetal malformations. However, it is still recommended to have a 4D ultrasound in mid-pregnancy to screen for fetal malformations in order to better understand the intrauterine condition of the fetus. Regular prenatal checkups are recommended during pregnancy to detect any anomalies in the pregnancy and the fetus at an early stage.