Prenatal assessment of fetal chromosomal and genetic disorders through maternal plasma DNA analysis.

The existence of cell free DNA derived from the fetus in the plasma of pregnant women was first demonstrated in 1997. This discovery offered the possibility of non-invasive sampling of fetal genetic material simply through the collection of a maternal blood sample. Such cell free fetal DNA molecules in the maternal circulation have subsequently been shown to originate from the placenta and could be detected from about 7 weeks of gestation. It has been shown that cell free fetal DNA analysis could offer highly accurate assessment of fetal genotype and chromosomal makeup for some applications. Thus, cell free fetal DNA analysis has been incorporated as a part of prenatal screening programs for the prenatal management of sex-linked and sex-associated diseases, rhesus D incompatibility as well as the prenatal detection of Down's syndrome.Cell free fetal DNA analysis may lead to a change in the way prenatal assessments are made.