Grand Rounds are usually done at around 20-24 weeks of pregnancy. Too small a gestational week, where the fetal organs are not mature, or too large a gestational week, where the fetal body has too much fat deposits, will affect the results of 4D ultrasound. Grand mal is a 4D dynamic color ultrasound examination, which can display the face of the fetus, the development of each organ in three dimensions, and the activity of the fetus in the mother’s body. It can diagnose fetal abnormalities, such as cleft lip, cleft palate, abnormal bone development and cardiovascular malformations, at an earlier stage. However, 4D ultrasound can not rule out all malformations, and a 3D ultrasound examination is needed at 28-30 weeks of pregnancy to supplement and improve the 4D ultrasound examination, which can screen out 95% of fetal malformations. In addition, it is recommended that pregnant women eat more food before these two examinations and walk appropriately to get the baby moving so that they can have a more comprehensive view.