The 4D ultrasound fetal examination is usually normal, but there are very few cases of malformations, such as craniosynostosis, spina bifida and spinal cord spondylolisthesis, ventral bifida, cartilage dysplasia, lateral ventricular widening, hydrocephalus, and malformed heart development. For example, single ventricle, single atrium, tricuspid atresia, tricuspid valve inferior displacement malformation, severe pulmonary stenosis or atresia, primary foramen ovale atrial septal defect, complete atrial septal defect, hypoplastic left heart syndrome, ventricular septal defect, tetralogy of Fallot, common arterial trunk malformation, and complete transposition of the great arteries.