Cell-free DNA versus intact fetal cells for prenatal genetic diagnostics: what does the future hold?

Prenatal screening and diagnosis is currently focused on the development of a noninvasive prenatal diagnostic test capable of detecting abnormalities similar to those attainable with an invasive test. One contender is cell-free fetal DNA circulating in maternal plasma and the other is intact fetal cells either from the maternal blood or the cervix. Once adequate fetal DNA is available, laboratory analytic techniques, such as sequencing and microarray, can be applied allowing detection of most cytogenetic and Mendelian fetal disorders. The question is: how close are we to achieving this feat, and what does the future hold?