Do four-dimensional ultrasound should pay attention to the examination time, preparation before the examination and so on. 1. Examination time: four-dimensional ultrasound is usually to be carried out in 20-24 weeks of pregnancy, but before that, you should make an appointment for four-dimensional ultrasound examination in advance. Pregnant women have to go to the hospital for the examination at the appointed time. Before the examination, you can change your posture and take a walk so that the baby can reach the best position and you can see the full view of the baby. 2. Preparation before the examination: Before the examination, pregnant women can eat and do not need to hold urine. It is best for pregnant women to wear loose clothing so that it is convenient for the examination. The examination time of 4D ultrasound is relatively long, so pregnant women should be psychologically prepared. If the position of the fetus is not good during the examination, pregnant women also need to walk around and check again. Four-dimensional ultrasound can check fetal malformation, is an important examination during pregnancy, pregnant women should pay attention to do a good job at the specified time. Meanwhile, they should pay attention to regular maternity checkups in order to observe the condition of the fetus.