The 4D ultrasound examination during pregnancy is a very important intentional examination in the middle of pregnancy, which is mainly used to detect fetal malformations and evaluate the growth and development of the fetus in the womb. It mainly refers to a means of detecting the state of the fetus, the main feature is that it is more three-dimensional and can observe the dynamic changes of the fetus in the mother’s womb and can better screen the state of the fetus, so it is one of the most commonly used ultrasound examinations at present, and the examination contained in it has several aspects: 1. Facial detection of the fetus, checking whether there are any deformities. The fetal face is examined to see if there are any defects in the nose, eyes, etc., and if there are any hare lips; 2. The fetal heart is examined to see if there are any problems, similar to congenital heart disease; 3. The limbs are examined to see if the fetal limbs are sound and if there are any defects; 4. The fetal urinary system is examined to see if the fetal urinary system is well developed, and the kidney organs are examined for damage, integrity, urethral obstruction, and hydronephrosis, polycystic kidney, etc.; 5. The testing of the nervous system, which is especially important, is needed to understand whether there are some diseases in the child’s brain, such as common anencephaly, spina bifida, etc.; 6. Check whether there are abnormalities in the fetal digestive system, such as visceral ectopia, intestinal atresia, etc.; 7. Understand the developmental environment of the fetus. Whether the amount of amniotic fluid is too little or too much, whether the placenta is abnormal, etc. It can be seen that most of the pregnant women think ultrasound examination is to check the development of the fetus in the middle of pregnancy, in order to detect fetal malformations and other diseases in time for early intervention measures.