NT is an important examination at the stage of pregnancy (11-13) weeks + 6 days, mainly through ultrasound examination to measure the thickness of the nuchal translucency layer, which is also an important indicator to determine whether the fetus has abnormalities. NT1.3mm is the thickness of the nuchal translucency layer of the fetus 1.3mm, which is within the normal range. The normal value of NT is below 2.5mm, but NT1.3mm does not mean that the fetus does not have abnormalities, and should continue to be observed and regular maternity checkups. For example, Down’s syndrome screening is performed at (15-20) weeks + 6 days of pregnancy to rule out the possibility of Down’s syndrome, and 4D ultrasound is performed at 20-24 weeks to rule out the possibility of fetal abnormalities and to make a comprehensive judgment of fetal development. In addition, NT ≥ 2.5mm is considered as an abnormal condition, suggesting chromosomal abnormalities or fetal malformations, such as heart malformations, which require further prenatal diagnosis. Prenatal diagnosis includes non-invasive DNA test and amniocentesis, which can clarify the presence of fetal anomalies. In addition, further ultrasound examinations are needed to provide symptomatic management according to the findings and etiology. If repeated examinations show abnormal NT values, amniocentesis can be performed to determine if there are chromosomal abnormalities.