Abstract: Down syndrome (DS) is one of the important reasons for the intelligence congenital deformity in children. Regular prenatal diagnosis is not satisfied due to the invasive procedures, such as amniocentesis and chorionic villus sampling. Nowadays, the non-invasive cell-free DNA (cfDNA) screening and diagnosis can avoid those invasive procedures. The application of cfDNA test with the peripheral blood of pregnant women in the non-invasive prenatal screening and diagnosis of DS and other genetic diseases has received extensive attention in the field of prenatal diagnosis. Although the cfDNA diagnosis technology has been greatly developed in recent years, there are still many problems to be solved, such as technical, legal and social issues, before its extensive use. In this paper, the non-invasive cfDNA and its application in prenatal diagnosis were reviewed.

Key words: Prenatal diagnosis, Down syndrome, DNA, Informed consent, Ethics, medical