() Cohort III-2 193,638 Aim: to determine the risk of missing other 10,205 (5.3%) pregnancies had cytogenetic Study assumed study abnormal karyotypes of probable or molecular analysis performed. Of that cfDNA phenotypic significance by cfDNA testing. 1,122 (11.0%) had an abnormal karyotype, testing would of which 262 (23.4%) would have been have 100% Setting: Denmark missed by CFDNA TESTING, but would sensitivity for Population: singleton pregnancies booked probably have been clinically significant. trisomies 21, 18 for combined first trimester screening over a The prevalence of such 'atypical abnormal and 13 and sex 4-year period karyotypes' was increased in women over 45 chromosome Methods: Data concerning maternal years of age, in pregnancies with increased aneuploidy. demographics, cFTS and prenatal or nuchal translucency (NT) thickness (> 3.5 postnatal karyotypes were collected from mm), with abnormal levels of free the Danish Medicine database. chorionic gonadotropin (<0.2 or > Karyotypes were classified according to 5.0 multiples of the median [MoM]) or whether the chromosomal anomaly would pregnancy-associated plasma have been detected by cfDNA testing and MoM. One or more of these factors whether it was likely to affect phenotype. was present in 3% of women, and the prevalence of atypical abnormal karyotypes in this high-risk cohort was 1.6%.
() Cohort study III-2 193,638 Aim: to determine the risk of missing other abnormal karyotypes of probable phenotypic significance by cfDNA testing. Setting: Denmark Population: singleton pregnancies booked for combined first trimester screening over a 4-year period Methods: Data concerning maternal demographics, cFTS and prenatal or postnatal karyotypes were collected from the Danish Medicine database. Karyotypes were classified according to whether the chromosomal anomaly would have been detected by cfDNA testing and whether it was likely to affect phenotype. 10,205 (5.3%) pregnancies had cytogenetic or molecular analysis performed. Of 1,122 (11.0%) had an abnormal karyotype, of which 262 (23.4%) would have been missed by CFDNA TESTING, but would probably have been clinically significant. The prevalence of such 'atypical abnormal karyotypes' was increased in women over 45 years of age, in pregnancies with increased nuchal translucency (NT) thickness (> 3.5 mm), with abnormal levels of free chorionic gonadotropin (<0.2 or > 5.0 multiples of the median [MoM]) or pregnancy-associated plasma MoM. One or more of these factors was present in 3% of women, and the prevalence of atypical abnormal karyotypes in this high-risk cohort was 1.6%. Study assumed that cfDNA testing would have 100% sensitivity for trisomies 21, 18 and 13 and sex chromosome aneuploidy.
cfDNA%20testing%20evidence%20evaluation%2016May17.docx