The failure of 4D ultrasound depends on what causes the failure. It depends on whether the fetus has an organ malformation, or whether certain structures are not displayed due to the pregnant woman’s own obese abdominal wall, or the fetus’ poor position. If it is due to a problem with the fetal organ structures, the patient will need to undergo further non-invasive DNA or even an amniocentesis biopsy to determine if the fetus has chromosomal and other abnormalities. If it is due to the pregnant woman’s own obese abdominal wall, the patient will need to be examined several times or choose a better general hospital and get another examination by an experienced doctor. If the fetus is in a bad position and some structures are not showing, let the pregnant woman move more and then re-examine, or let her eat and let the fetus move before examining.