Clinical experience of noninvasive prenatal testing with cell-free DNA for fetal trisomies 21, 18, and 13, in a general screening population.

OBJECTIVE Evaluate noninvasive prenatal testing (NIPT) with cell-free DNA as a screening method for trisomies 21, 18, and 13 in an obstetrical clinical practice setting. METHODS Observational study of pregnant women who underwent prenatal screening for fetal trisomy from 30 July 2012 to 1 December 2012. NIPT was offered to all patients in addition to first trimester combined screening (FTS). RESULTS The cohort included 289 women with mean age of 32.3 years (range: 17.8-42.0) who underwent testing at 13.0 gestational age weeks (range: 10.1-20.7). NIPT results were provided for 98.6% of patients at a mean reporting time of 9.3 calendar days. With NIPT, all patients had a risk less than 1:10 000 for trisomy 21, 18, or 13. With FTS, 4.5% of patients had screening results indicating an increased risk for trisomy 21. One patient who had an elevated trisomy 21 risk with FTS elected to have an amniocentesis, which revealed a euploid fetus. CONCLUSIONS NIPT has the potential to be a highly effective screening method as a standard test for risk assessment of fetal trisomies 21, 18, and 13 in general pregnant populations.