Recently it was identified that during pregnancy, there is fetal DNA in maternal blood in sufficient quantities to be analysed and methods have been proposed to detect the presence or not of a fetus with Down syndrome using maternal blood. The introduction of genomic blood testing as proposed in the context of this project could lead to increased detection of Down syndrome, less invasive screening, and preventing the accidental loss of 70 normal fetuses, at a lower overall cost than current practice. However, these methods still need to be validated before being appropriately introduced in routine care. This project proposes to carry out an independent study that will validate the performance and utility of these new genomic technologies for screening in pregnant women using maternal blood. The deliverables of this project will enable decision makers, pregnant women and their partner to make informed choices pertaining to prenatal genetic screening and diagnosis, such as screening for Down syndrome, and reduce the risk to pregnancies associated with amniocentesis.