Noninvasive dna trisomy 21 high risk, amniocentesis normal probability is relatively low. Non-invasive DNA, that is, fetal chromosome aneuploidy non-invasive genetic testing, is a common screening tool for chromosomal abnormalities in mid-pregnancy, screening for the risk of fetal disorders of trisomy 21-trisomy 21, trisomy 18-trisomy 18, trisomy 13-trisomy 13, with an accuracy of 99%, non-invasive DNA suggests a high risk, which can’t be taken as the final result, and it is still necessary to improve the prenatal diagnosis such as amniocentesis, so as to make clear whether or not there is chromosomal abnormality in the fetus. Non-invasive DNA has a higher accuracy rate than Down’s syndrome screening, but it still has certain limitations. For pregnant women with suspected fetal developmental abnormalities, or with one of the spouses suffering from congenital diseases or a family history of genetic disorders, they should inform their obstetricians of their conditions in a timely manner, and choose the appropriate test under the guidance of a specialized doctor.