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.