VP03.04: First trimester aneuploidy screening using maternal characteristics, serum biochemical markers and nuchal translucency in a low‐risk population

Abstract

The aim of the study was to evaluate the changes in diagnostics of Trisomy 21 in a 10 mil population between 1994-2018. Methods: Data from the national registries. Results: There were 5496 fetuses with trisomy 21 in the studied period. The detection rate increased from 40.7% (1994) to 87.66 (2018). The number of invasive procedures varied between 1757.6/10000 newborns (2007) and 580.9/10000 newborns (2018). Indications for invasive testing were 80% combined first-trimester screening (FTS) and 20% morphologic findings on ultrasound and second-trimester screening. The number of trisomy 21 newborns per 10000 decreased from 7.79 in 1994 to 3.42 in 2018. The gestational age at the final diagnosis decreased from 20.33 weeks in 1994 to 14.24 weeks in 2018. Since 2015, 122 cases of Trisomy 21 were detected with NIPT. Conclusions: Since 1994 the screening methods developed to FTS and NIPT. The Trisomy 21 screening has already in 2006 reached a plateau: the percentage of detected cases in the whole population exceeded 80% and was improving until 2020 to 87.6%. High sensitivity and specificity of FTS caused a steep decrease in invasive procedures. In the same time period, the maternal age was significantly increased without affecting the detection rates. We could not assess the effect of NIPT due to the small number of examinations. It can not be expected, that in real life, higher detection rates would be achieved in the whole population, even with new, more sensitive technologies. Research grant provided by the Czech Ministry of Health AZV17-29622A and RVO-VFN64165.