Usually, pregnant women are tested around 10-14 weeks of pregnancy for NT, which refers to the thickness of the nuchal translucency and can be used to screen for congenital abnormalities in the fetus. The NT value is considered normal when it is <2.5mm. Any measured value greater than or equal to 2.5mm is diagnosed as cervical zona pellucida thickening. Cervical hyaline thickening is closely associated with a variety of fetal congenital anomalous disorders, such as chromosomal abnormalities and cardiovascular system anomalies. The most common of chromosomal abnormalities, trisomy 21, can be screened for early. The posterior cervical zona pellucida grows with the fetus but fades away after 14 weeks of gestation. There are also some individual cases with NT values >3mm, which do not necessarily mean that the fetus has a congenital disorder at this time due to the high amount of fetal fluids that affect the measurement. At this time, it should be closely observed, and in the middle of pregnancy, we should continue to perform malformation screening tests, such as amniocentesis and Down’s syndrome screening. Therefore, the NT value within the normal range can effectively reflect the health of the fetus, but abnormal NT value does not necessarily mean that there is a problem with the fetus, and it needs to be combined with other tests to confirm the diagnosis. Even if problems are found, it is important to follow the doctor’s advice for symptomatic treatment. Therefore, NT test at 10-14 weeks of pregnancy has become an essential test during pregnancy to help diagnose the presence of congenital disorders in the fetus by the normal or abnormal NT value.