NT is also known as nuchal translucency thickness, and non-invasive is also known as non-invasive DNA. If there is no abnormality after doing non-invasive DNA with a high NT, then there is no need to do amniocentesis, and if there is any abnormality in the result of the test, then you can further do amniocentesis. Pregnancy 11~13+6 weeks can go to the hospital to do NT examination, through the thickness of the nuchal translucency layer to determine whether the fetus has chromosomal abnormalities, the results of the examination is relatively high need to further do non-invasive DNA examination, the results of the examination for the low-risk do not need to do amniocentesis examination, the results of the examination for the high-risk have to further do amniocentesis examination. Non-invasive DNA belongs to the prenatal screening method, through the extraction of maternal venous blood to detect the probability of the fetus suffering from chromosomal abnormalities, while amniocentesis belongs to the prenatal diagnostic method, in which ultrasound-guided extraction of amniotic fluid is used for further examination, to ascertain whether the fetus suffers from chromosomal abnormalities, and the accuracy rate of the amniocentesis examination is higher than that of non-invasive DNA examination. If the results of the amniocentesis test are normal, the pregnancy can continue, but if the results are abnormal, it is important to carefully consider whether to continue the pregnancy.