In a general obstetrical population, prenatal testing with the use of cfDNA had significantly lower false positive rates and higher positive predictive values for detection of trisomies 21 and 18 than standard screening. (Funded by Illumina; ClinicalTrials.gov number, NCT01663350.).

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The 1997 discovery of free fetal DNA in maternal plasma launched clinical researchers' efforts to establish a reliable method for non-invasive prenatal testing for fetal genetic conditions. Various methods, including, but not limited to, massively parallel sequencing (MPS) and selective analysis of cell-free fetal DNA in maternal plasma, have recently been developed as highly sensitive and specific noninvasive screening tools for common fetal chromosome aneuploidies. Incorporating these new noninvasive technologies into clinical practice will impact the current prenatal screening paradigm for fetal aneuploidy, in which genetic counseling plays an integral role. The National Society of Genetic Counselors (NSGC) currently supports Noninvasive Prenatal Testing/Noninvasive Prenatal Diagnosis (NIPT/NIPD) as an option for patients whose pregnancies are considered to be at an increased risk for certain chromosome abnormalities. NSGC urges that NIPT/NIPD only be offered in the context of informed consent, education, and counseling by a qualified provider, such as a certified genetic counselor. Patients whose NIPT/NIPD results are abnormal, or who have other factors suggestive of a chromosome abnormality, should receive genetic counseling and be given the option of standard confirmatory diagnostic testing.

What's already known about this topic? Noninvasive prenatal testing for detection of trisomies 21, 18, and 13 is clinically available and is reported to have a false positive rate of 1% or less This technology utilizes massively parallel shotgun sequencing of cell‐free DNA, of maternal and placental origin, present in maternal plasma What does this study add? Unexplained abnormal noninvasive prenatal testing results should prompt consideration of a maternal source of the abnormal cell‐free DNA, such as malignancy