Pregnant women can choose the time when the fetus moves frequently to have the 4D ultrasound examination, and they can also have proper exercise and supplement energy to increase the fetal movement, which in turn will improve the passing rate of the 4D ultrasound. 1. Choose the right time: pregnant women can choose the time when the fetus moves frequently to choose to carry out 4D ultrasound examination. If the fetus moves frequently in the morning, you can choose to have the 4D ultrasound examination in the morning, and if the fetus moves frequently in the afternoon, you can choose to have the examination in the afternoon. The 4D ultrasound examination at the time of frequent fetal movement can maximize the possibility of observing all parts of the fetus. 2. Appropriate exercise: If pregnant women find that the fetus is not moving actively before the 4D ultrasound examination, they can do appropriate exercise, such as walking, climbing stairs and other stimulating fetal movement. 3. Supplemental energy: Fetal movement will also decrease when the fetus is in the state of maternal starvation, so the pregnant woman can supplement some energy appropriately to increase the frequency of fetal movement. If the 4D ultrasound results appear abnormal, you need to consult a doctor in time and take appropriate methods to deal with it.