The NT test is an important indicator to determine whether the fetus has chromosomal or structural abnormalities by measuring the thickness of the skin folds at the back of the fetus’s neck through ultrasound. However, NT screening is affected by various factors such as the testing instrument, fetal position, fetal size and gestational week, and a normal test result does not mean that the fetus is normal. Therefore, if you are not sure about the test result or if the test result shows a critical risk, it is recommended that further tests such as Down’s syndrome screening, non-invasive DNA testing and amniocentesis should be performed under the guidance of a doctor to clarify the diagnosis. In addition, in order to avoid the birth of the affected child, pregnant women should pay attention to ensure sufficient sleep and rest time, avoid exposure to radiation, toxic and harmful substances and other undesirable environments in the early stages of pregnancy, conduct regular maternity checkups, and if fetal abnormalities are detected, improve the relevant tests as soon as possible and provide symptomatic treatment according to the situation.