Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology
-
Ultrasound Obstet Gynecol · Apr 2018
Comparative StudyContingent first-trimester screening for aneuploidies with cell-free DNA in a Danish clinical setting.
The primary aim of this study was to compare the screening performance for trisomy 21 (T21) between combined first-trimester screening (cFTS) with referral for invasive testing at a T21 risk ≥ 1 in 300, and contingent screening consisting of referral for invasive testing at a cFTS-T21 risk ≥ 1 in 100 and referral for cell-free DNA (cfDNA) testing at a cFTS-T21 risk between 1 in 100 and 1 in 1000. Secondary aims were to compare the incidence of fetuses diagnosed with trisomy 18 (T18), trisomy 13 (T13) or sex chromosome aneuploidy, and examine the association between fetal fraction of cfDNA in maternal blood and maternal/fetal characteristics. ⋯ In a clinical setting with efficient cFTS, contingent screening offering women with a cFTS risk of ≥ 1 in 100 an invasive test and women with a risk from 1 in 100 to 1 in 1000 a cfDNA test had the same sensitivity for T21, T18 and T13, but significantly increased specificity, when compared with offering an invasive test to all women with a risk of ≥ 1 in 300. Implementing contingent screening would therefore reduce significantly the number of invasive tests performed at no loss of sensitivity. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.