The normal value of NT test is <2.5mm in some hospitals and <3.0mm in others, NT thickening is associated with fetal chromosomal abnormalities and structural malformations and further prenatal diagnosis should be performed. If the test is not performed within this time frame, the NT value may be poor, resulting in unreliable results. If none of the above, further chorionic villus aspiration or amniocentesis can be performed as prescribed by the doctor to check the fetal chromosomes. If the pregnant woman has concerns about the risk of aspiration, she can also opt for non-invasive DNA testing, but it should be noted that non-invasive DNA is only a screening test with false positives and false negatives, and further amniocentesis is required for high risk of non-invasive DNA. If the amniocentesis test results are not abnormal, the fetus can usually be retained, but intensive labor and delivery is required. If amniocentesis suggests abnormality, termination of pregnancy is usually required. In addition, NT thickening is associated with fetal structural malformations and attention should be paid to fetal structural malformations in the middle of pregnancy. Fetal echocardiography is recommended for NT ≥ 3 mm. Prenatal checkups should be enhanced during pregnancy, NT screening should be actively performed at the appropriate time to avoid unnecessary stress and to pay attention to the fetal condition to ensure the health of the fetus and the pregnant woman.