Multicentre study “Prenatal diagnosis of Down syndrome in Russia 2005–2015”. II. Ultrasound markers

Abstract

Objective: to study the effectiveness of the use of ultrasound markers for Down syndrome (DS) in the fetus during ultrasound examinations at 11–14 and 18–21 weeks of gestation based on the results of multicentre analysis in the regions of Russia in 2005–2015 years. Materials. The analysis was based on data from a questionnaire on prenatal diagnosis of DS in 30 regions and cities of Russia in 2015. The data from the questionnaire survey of 12 regions in 2005 and 23 regions in 2010 for analyse the dynamic of prenatal diagnosis of DS in our country was obtained. The questionnaire included the questions about the number of births and pregnant women registered in the region; the total number of cases of DS registered in prenatal and postnatal periods; structures of diagnosed cases of DS depending on the detection period; indications for prenatal karyotype; the number of fetuses with DS and the increase of nuchal translucency in 11–14 weeks of gestation; ultrasound markers of DS in the II trimester of gestation and perinatal outcome in cases of prenatal diagnosis of DS. Results. In the course of the multicentre analysis it was established that the accuracy of identification of DS in the prenatal period in our country was 30,9% in 2005, 38,4% in 2010 and significantly increased to 59,7% in 2015. In 2005, only 17,2% of cases of DS were detected in 11–14 weeks of gestation, in 2010 — 38,2% and increased to 72,1 % (7,6–100%) in 2015. In 24 from 30 regions the proportion of diagnosed cases of trisomy 21 at 11–14 weeks of gestation was 50% or more, and in 11 regions — 90–100%. Increase of nuchal translucency thickness was detected on average in 76,3 % fetuses with DS with a range from 28,1 to 100 %. The most prenatal ultrasound markers in fetuses with DS in the second-trimester were congenital malformations and hypoplasia / absence of nasal bones — 64,9 and 65,5 %, respectively. Further, as the frequency of detection decreased: prenasal thickness (27,6 %), echogenic intracardiac focus (27,1%), pyelectasis (22%), nuchal fold (19,7%), short humerus/femur (17,5%), hyperechogenic bowel (14,6%), ventriculomegaly (11,2%), choroid plexus cysts (7,3%). Conclusion. Ultrasound examination is powerful method for identification the fetuses with DS. Therefore, it is necessary to continue the development of new ultrasound markers of DS for improving its prenatal diagnosis.