4D generally refers to 4D ultrasound during pregnancy, and pregnant women can visit their doctor for the examination between 20 and 28 weeks of pregnancy. 4D ultrasound examination is one of the important examinations during pregnancy, which can dynamically and continuously show the activities of the fetus in the uterus. Women during pregnancy can also use 4D ultrasound to diagnose whether the fetus is malformed, such as cleft lip and palate, anencephaly, hydronephrosis, megacolon, etc. It has an important clinical application value, and can be chosen to be performed between the 20th and 28th weeks of pregnancy. Pregnant women can do simple exercise or eat moderately before the 4D ultrasound to ensure that the examination is done when the fetus is moving frequently to ensure the accuracy of the examination results. For those with abnormal 4D ultrasound results, other tests such as amniocentesis can be done to clarify whether the fetus is malformed, so as to choose to continue the pregnancy or terminate the pregnancy according to the actual situation and after the doctor’s assessment. Pregnant women are advised to consult regular hospitals for 4D ultrasound, which will not affect themselves or their fetuses, so they should adjust their mindset and actively cooperate with medical personnel.