If the Down’s syndrome screening is a critical risk, the baby may or may not have chromosomal abnormalities after birth, which cannot be accurately determined. For the sake of eugenics and parenting, it is best to do non-invasive DNA testing, which has a 99% chance of accuracy. The non-invasive DNA prenatal testing technology only requires taking the venous blood of pregnant women, using the new generation DNA sequencing technology to sequence the free DNA fragments in the maternal peripheral plasma, including the free DNA of the fetus, and the sequencing results will be analyzed for bioinformatics, from which the genetic information of the fetus can be obtained, so as to detect whether the fetus is suffering from the three major chromosomal diseases. If there are no problems with doing non-invasive DNA, the baby can be born without any problems. If there is a high risk of doing non-invasive DNA, further amniocentesis is required and the results of amniocentesis, which is a final test result.