Non-invasive DNA testing suggests chromosomal abnormalities, and the probability of a normal amniocentesis is very small. Non-invasive DNA is a means of prenatal screening, also known as fetal chromosome aneuploidy non-invasive genetic testing, the accuracy rate of about 99% or more, is a commonly used means of screening chromosomal abnormalities during pregnancy, non-invasive DNA, such as suggesting chromosomal abnormality of high-risk, can not be taken as the final result, need to perform amniocentesis for definitive diagnosis, and amniocentesis results in a normal probability of about 1%. Down’s syndrome, non-invasive DNA and amniocentesis are commonly used clinical screening or diagnosis of chromosomal abnormalities in fetuses, and their examination weeks and adaptable targets are different, so you should choose the appropriate examination method for yourself under the advice of professional doctors during pregnancy.