Four-dimensional that is, four-dimensional ultrasound, do four-dimensional ultrasound before, it is recommended to make an appointment in advance, grasp the time of the maternity examination, pay attention to diet, wear loose-fitting clothes and so on. 1. Make an appointment in advance: It’s best to make an appointment with your doctor before having a 4-D ultrasound so you don’t have to wait in line to avoid fatigue. 2. Grasp the time of the maternity examination: four-dimensional color ultrasound examination is limited to a certain range of time, it is recommended that the examination be carried out in 20 to 24 weeks of pregnancy, at this stage, the overall structure of the fetus has been formed, and the size of the fetus and the amniotic fluid volume is moderate, so that the fetus image can be clearly observed. 3. Pay attention to diet: before the 4D ultrasound examination, you can eat appropriately, which will help the fetus to move around and can make the examination more smoothly. 4. Wear loose clothes: It is recommended to wear loose clothes during the 4D ultrasound examination, which is convenient to reveal the examination area and shorten the examination time. Each hospital may hui the things that need to be prepared before doing 4D ultrasound, it is recommended to take the preparations required by the hospital as the basis.