The main malformations caused by thickening of soft tissues in the fetal neck include Down’s syndrome, cardiac malformations, thalassemia, thoracic hypoplasia and other chromosomal disorders. 1. Down’s syndrome: chromosome 21, 18, 13 trisomy abnormalities will lead to Down’s syndrome, mainly affecting the intellectual aspect. 2. Cardiac malformation: chromosomal abnormalities may cause incomplete heart development, such as mitral tricuspid valve regurgitation and other congenital heart diseases. 3. Thalassemia: Thalassemia is also a disease caused by chromosomal abnormality, mainly because babies born with this gene are easy to cause long-term chronic anemia. 4. Thoracic Hypoplasia: It refers to the incomplete development of the thorax of the fetus in the uterine cavity, and this condition will affect the survival rate of the fetus. Fetal neck soft tissue thickening is mainly because there is a possibility that the fetus has chromosome-related diseases, so if abnormalities are detected by screening, further examination must be carried out to make sure to avoid delays.