The nt test is an important part of the prenatal checkup for pregnant women and is designed to screen the fetus for congenital anomalies. The nt examination is a kind of fetal ultrasound examination, non-invasive and painless. The following points need to be noted before the nt examination: first, pay attention to the time of the examination. Pregnant women nt examination is strictly limited to the examination time. It is required that the nt examination be performed at 11 weeks-13 weeks + 6 days of pregnancy. If this time is exceeded, then the nt examination cannot be performed. Second, the relevant preparation before the examination. Pregnant women do not need to fast before the nt test, so in order to avoid the occurrence of hypoglycemia, so it is recommended that pregnant women have the test after eating. Before the examination, there is no need to hold urine, so pregnant women can drink water and urinate normally. However, it should be noted that generally more pregnant women undergo NT examination, so they need to wait for some time during the examination. It is recommended that pregnant women and their families be prepared to wait. It is best to make an appointment in advance for the nt test to avoid waiting too long. To summarize, before undergoing an nt test, one should carefully account for the gestational week and ensure that the test is conducted within the required time frame.