Performance of screening for aneuploidies by cell-free DNA analysis of maternal blood in twin pregnancies.

Objectives: To report clinical implementation of cell-free DNA (cfDNA) analysis of maternal blood in screening for trisomies 21, 18 and 13 in twin pregnancies and examine variables that could influence the failure rate of the test.

Methods: cfDNA testing was performed in 515 twin pregnancies at 10-28 weeks' gestation. The failure rate of the test to provide results was compared with that in 1847 singleton pregnancies, and logistic regression analysis was used to determine which factors among maternal and pregnancy characteristics were significant predictors of test failure.

The first 3,000 Non-Invasive Prenatal Tests (NIPT) with the Harmony test in Belgium and the Netherlands.

As the classical first trimester Down syndrome screening (FTS, combination test) has a false-negative rate of 20-25% and > 95% of the abnormal FTS results are false-positive, we evaluated the new Non-Invasive Prenatal Test (NIPT) in Belgium and the Netherlands. The study population consisted of 3000 consecutive pregnancies in Belgium and the Netherlands in which NIPT was performed using the Harmony test. In 57 (1.