DNA sequencing is changing prenatal screening, writes Jane Brody in her New York Times health column. New prenatal tests look at cell-free DNA from the fetus that is floating in the woman's blood and, Brody notes, appear to be accurate and can be performed early in a pregnancy. Currently, the tests mainly look for trisomies, like trisomy 21.
However, Brody adds that the tests, currently offered by four companies, are not yet approved by the US Food and Drug Administration and are not considered diagnostic, meaning that a positive result needs be confirmed through an amniocentesis or chorionic villus sampling. Additionally, she notes that the noninvasive prenatal screens are recommended at the moment for women at high risk of having a child with a chromosomal abnormality
"Prenatal diagnosis, today a routine part of obstetric care, has made great strides since the mid-1970s and is now on the cusp of further revolutionary developments," Brody says.