The time required for a 4D ultrasound is relatively long and may be around 30-40 minutes. If the fetus is uncooperative and the fetal position obscures part of the limb, the part to be examined cannot be seen during the examination, and the examination may take longer. During the examination, the examination may be temporarily suspended to allow the pregnant woman to move appropriately, which can facilitate the change of the fetal position to make the examination more comprehensive. Most of the abnormalities can be detected, such as cleft lip and palate, anencephaly, hydrocephalus, congenital spina bifida, abnormal limb development, abnormal facial development, abnormal development of the five senses, etc. The results of 4D ultrasound examination may not be 100% accurate because of the influence of fetal position and other factors. During the 4D ultrasound examination, some doctors will print the fetal face picture as the first picture of the baby, which can be kept as a souvenir.