Four-dimensional is also known as four-dimensional color ultrasound, four-dimensional color ultrasound once through, need to choose the right time to check, eat before the examination, appropriate activities before the examination, adjust the mentality and so on. 1. Choose the right time to check: four-dimensional color ultrasound in pregnancy 22 ~ 28 weeks check is more appropriate, this stage of fetal basic development, intrauterine amniotic fluid volume is moderate, the activity is better, easy to pass the examination, the examination time should not be too early or too late. 2. Eating before the examination: you can eat properly before the examination, don’t go to the examination on an empty stomach, after eating, the sugar in the blood increases, the fetus is more active in the uterus, and it is easy to pass the 4D examination. 3. Appropriate activities before the examination: appropriate activities before the examination, such as walking, climbing stairs, so that the fetus in the uterus to move up, do the examination is also easy to pass. 4. Adjust the mindset: women should have a correct understanding of the four-dimensional ultrasound, and adjust their mindset before doing the examination, do not be too nervous. After pregnancy, do a good job of pregnancy maternity examination, there are abnormalities in time to seek medical attention.