Based on the 1997 discovery of cell-free fetal DNA (cffDNA) in maternal blood, non-invasive prenatal testing (NIPT) allows the fetal genome to be tested from a sample of the mother’s blood. Existing uses include the identification of fetal blood group, the determination of fetal sex (when at risk of sex-linked diseases) and the detection of chromosomal abnormalities, including Down syndrome.
NIPT avoids the risk of miscarriage associated with invasive testing procedures (e.g. amniocentesis or chorionic villus sampling) and the sensitivity and specificity of NIPT approaches 100% for detecting Down syndrome, providing the sequencing is successful. However, technical, financial and ethical issues remain as NIPT becomes a primary screen for those women who wish to know about fetal chromosomal abnormality. Since these tests are increasingly being chosen, all obstetricians will need to be aware of the issues raised.
This updated Scientific Impact Paper, written by experts in the field – former chair of the Fetal Anomaly Screening Programme steering committee, Professor Peter Soothill, and the discoverer of cffDNA, Professor Dennis Lo – summarises current evidence and issues in this area, with particular emphasis on the detection of chromosomal abnormalities.