Initial experience with non-invasive prenatal testing of cell-free DNA for major chromosomal anomalies in a clinical setting

Abstract

Objective: To evaluate non-invasive prenatal testing (NIPT) of cell-free DNA (cfDNA) as a screening method for major chromosomal anomalies (CA) in a clinical setting.

Methods: From January to December 2013, Panorama™ test or Harmony™ prenatal test were offered as advanced NIPT, in addition to first-trimester combined screening in singleton pregnancies.

Results: The cohort included 333 pregnant women with a mean maternal age (MA) of 37 years who underwent testing at a mean gestational age of 14.6 weeks. Eighty-four percent were low-risk pregnancies. Results were provided in 97.3% of patients at a mean reporting time of 12.9 calendar days. Repeat sampling was performed in six cases and results were obtained in five of them. No results were provided in four cases. Four cases of Down syndrome were detected and there was one discordant result of Turner syndrome. We found no statistical differences between commercial tests except in reporting time, fetal fraction and MA. The cfDNA fraction was statistically associated with test type, maternal weight, BMI and log βhCG levels.

Conclusions: NIPT has the potential to be a highly effective screening method for major CA in a clinical setting.

Keywords: Cell-free DNA; chromosomal anomalies; first-trimester screening; non-invasive prenatal testing; prenatal diagnosis; trisomy 21.