In fact, 3D and 4D cannot be fully used as a systematic screening ultrasound. The real observation of the fetus for malformations is done with 2D ultrasound. 3D ultrasound has its advantages in facial presentation, but many malformations can not necessarily be detected completely by 3D. It is only used as a supplement to two-dimensional ultrasound. Generally, in the early tanning stage, a 3D ultrasound can be done to get an overall view of the fetus. In mid-pregnancy, 3D ultrasound is also an option for systematic screening. However, it is not recommended in late pregnancy.