DNA Screening and Invasive Testing Show Similar Miscarriage Rates

Patients were randomized to receive either cfDNA testing followed by invasive testing procedures only when cfDNA tests results were positive (n = 1,034) or to receive immediate invasive testing procedures (n = 1,017). The cfDNA testing was performed using an in-house validated method based on next-generation sequencing.

The team reported that 0.8% of women had miscarriages before reaching 24 weeks gestation. The miscarriages occurred at 19.9 weeks gestation, on average, in both the invasive testing group and the group that received initial cfDNA screening. Even so, they noted that just 8.3% of women from the cfDNA screening arm of the study had gone on to get amniocentesis or chorionic villus sampling, compared to nearly 77% of women in the invasive testing arm of the study. In the cfDNA group, they found all 27 instances of trisomy 21, with a false-positive rate of 5.6%, along with one additional case of chromosomal abnormality. They detected 49 chromosomal abnormalities in the group that underwent invasive testing from the get-go, including 11 non-trisomy 21 chromosomal abnormalities.

The authors concluded that among women with pregnancies at high risk of trisomy 21, offering cfDNA screening, followed by invasive testing if cfDNA test results were positive, compared with invasive testing procedures alone, and did not result in a significant reduction in miscarriage before 24 weeks. The study was published on August 14, 2018, in the Journal of the American Medical Association.

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