4D generally refers to 4D ultrasound. Strictly speaking, Grand Rounds and 4D are not the same, while 4D ultrasound is an examination method of Grand Rounds. Grand mal refers to the systematic screening in 20-24 weeks of pregnancy to clarify whether the fetus has malformations. 4D ultrasound is a relatively new method of clinical examination, which can observe the fetal development in a dynamic and three-dimensional way. In addition to 4D ultrasound, screening for major abnormalities can also be performed by 2D and 3D ultrasound. 2D ultrasound is a flat static image, which is clearer and can clarify the fetal development in different gestational weeks and whether there are any abnormalities in the fetus. The 3D ultrasound can show the three-dimensional image of the fetus, and the 4D ultrasound has more time axis compared with it, which can observe the fetus’ activity dynamically in real time, and a CD will be given to the pregnant woman and her family after the examination, which contains dynamic images that can be kept as a souvenir. If the hospital does not have 4D ultrasound, 2D and 3D ultrasound can be done to perform a major teratology examination, which is generally clearer. If the pregnant woman wants to do 4D ultrasound more strongly, she can refer to other hospitals with relevant professional equipment for examination.