At present, the major public hospitals still focus on three-dimensional ultrasound examination, as long as the major fetal abnormalities, the price is about 200-400 yuan. 4D ultrasound is generally carried out mostly in private hospitals, and the price varies depending on the hospital. 4D ultrasound is currently the most advanced ultrasound examination in the world. It is recommended to do 4D ultrasound after 20 weeks of pregnancy, because there is still controversy about 4D ultrasound examination in early pregnancy. Especially before 12 weeks of pregnancy, 4D ultrasound is not recommended, and most 3D ultrasound will solve the common major problems.