On average, a clinical examination for a grand mal examination takes about 20-30 minutes, and for a more cooperative child it may take 15 minutes to complete the examination. However, if the child is uncooperative and the examination takes longer than 30 minutes, the doctor may need the pregnant woman to leave the ultrasound room to sit outside for a while, take a walk, or eat some food, and then come back to continue the examination, and may even need to go back and forth several times. Therefore, it is important for the pregnant woman to arrange sufficient time for the examination so that the doctor can see all the structures she wishes to see. Generally speaking, the major teratology examination takes longer for two reasons: 1) more items: the examination contains more items and takes longer time; 2) the fetus needs to cooperate: because some of the structures examined are in front of the fetus, while some are behind the fetus, or on the left or right, so the child needs to move or roll continuously during the examination, otherwise it is impossible to see all the structures from different Otherwise, it is not possible to examine all the structures from different angles.