Methods to Increase the Percentage of Free Fetal DNA Recovered From the Maternal Circulation

Abstract
Prenatal diagnosis is useful for managing a pregnancy with an identified fetal abnormality and may allow for planning and coordinating care during delivery and the neonatal period.1 A variety of prenatal diagnostic tests are available but have limitations. Noninvasive tests such as maternal serum marker testing and ultrasound can be used to screen for the presence of chromosomal abnormalities but are not definitive.2-5 On the other hand, invasive diagnostic tests (eg, amniocentesis, chorionic villus sampling, percutaneous umbilical blood sampling) for fetal chromosomal abnormalities are highly reliable, but the procedure used for each test carries a risk for loss of pregnancy.6,7 Many patients who are candidates for these tests decline them because of the risk of pregnancy loss.