Clinical professional term does not have the term of macroanomaly, usually ultrasound examination is divided into I, II and III screening, no matter three-dimensional or four-dimensional or commonly known as macroanomaly is the second level of screening, generally in the 22-26 weeks of pregnancy, three-dimensional or four-dimensional ultrasound, can be some of the malformations of the foetus to carry out screening. Around 22 weeks of pregnancy, fetal organs have grown and developed to a degree that can be examined, and the amniotic fluid volume and the size of the fetus are in a more appropriate state, you can basically observe the development of the fetus, so as to determine whether the fetus has organ malformations. Nine major malformations such as anencephaly, lobar anencephaly, severe meningoencephalocele, severe open spina bifida with spinal cord bulge, single ventricle, single aorta, double renal agenesis, severe thoracic and abdominal wall defects with visceral ectopia, and lethal hypoplasia of the limbs with severe shortening of the limbs, etc., are necessary to be checked out. In addition to the nine major malformations mentioned above, 3D or 4D can also screen the morphology, structural development and growth of each organ of the fetus, amniotic fluid volume, placenta, umbilical cord and blood flow. Regular checkups are required during pregnancy and should be performed according to the advice of a specialized obstetrician.