Prenatal diagnosis: update on invasive versus noninvasive fetal diagnostic testing from maternal blood

摘要

The modern obstetrics care includes noninvasive prenatal diagnosis testing such as first trimesternscreening performed between 11 and 14 weeks’ gestation and second trimester screeningnperformed between 15 and 20 weeks. In these screening tests, biochemical markers arenmeasured in the maternal blood with or without ultrasound for fetal nuchal translucency withnreported accuracy of up to 90%. Invasive procedures, including amniocentesis or chorionic villinsampling, are used to achieve over 99% accuracy. During these procedures direct fetal materialnis examined and, therefore, these tests are highly accurate with the caveat of a small risk fornpregnancy loss. Much research now focuses on other noninvasive highly accurate and risk-freentests that will identify fetal material in the maternal blood. Fetal cells and fetal DNA/RNA providenfetal information but are hard to find in an overwhelming background of maternal cells and innthe absence of specific fetal cell markers. The most experience has been accumulated with fetalnrhesus and fetal sex determination from maternal blood, with an accuracy of up to 100% bynusing gene sequences that are absent from maternal blood. Although not clinically applicablenyet, fetal cells, fetal DNA/RNA and fetal proteomics in combination with cutting edge technologynare described to prenatally diagnose aneuploidies and single-gene disorders.