NT is the fetal nuchal translucency thickness scan. NT test is a method to detect whether the fetus has Down’s syndrome. NT thickening is usually associated with fetal chromosomal abnormalities, and the higher the NT value, the higher the chance of the fetus having Down’s syndrome. If the NT value is between 3-6mm, it means the thickening is low and the risk of chromosomal abnormality is low; if the NT value is greater than 6mm, it means the chance of fetal abnormality is high. When NT thickening occurs, non-invasive DNA test and amniocentesis can be performed under doctor’s guidance for clear diagnosis. If no chromosomal abnormality is found after the test, it can be basically determined that there is no chromosomal number abnormality and regular maternity checkups can be performed. If the non-invasive DNA test reveals chromosomal abnormalities, further amniocentesis or chorionic villus biopsy must be performed to clearly diagnose the presence of Down’s syndrome, other chromosomal syndromes and heart problems. In severe cases, the pregnancy needs to be terminated under the guidance of a doctor. Pregnant women need to have regular maternity checkups to understand the growth of the fetus and rule out the possibility of abnormal development through comprehensive screening tests. In addition, pay attention to stay away from radiation, chemical substances and other toxic and harmful environments in daily life to ensure normal fetal growth and development.