open access

Vol 87, No 11 (2016)
ORIGINAL PAPERS Obstetrics
Published online: 2016-11-30
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Nasal bone in screening for T21 at 11–13 + 6 weeks of gestation — a multicenter study

Bartosz Czuba, Dawid Serafin, Piotr Węgrzyn, Wojciech Cnota, Mariusz Dubiel, Marek Mączka, Dariusz Zarotyński, Aleksandra Ruci, Mirosław Wielgoś, Krzysztof Sodowski, Dariusz Borowski
DOI: 10.5603/GP.2016.0082
·
Pubmed: 27958633
·
Ginekol Pol 2016;87(11):751-754.

open access

Vol 87, No 11 (2016)
ORIGINAL PAPERS Obstetrics
Published online: 2016-11-30

Abstract

 Objectives: Trisomy 21 is one of the most common chromosomal defects diagnosed prenatally. Screening for Down syndrome is based on maternal age, measurement of crown-rump length, nuchal translucency and fetal heart rate, together with free β-hCG and PAPP-A at 11 to 13 + 6 weeks. Introduction of additional ultrasound marker of trisomy 21 (evaluation of the nasal bone) may result in increased DR and decreased invasive diagnostic testing rates (FPR).
Material and methods: Ultrasound scan with NB evaluation was performed in 5814 fetuses during routine screening for chromosomal defects at 11 to 13 + 6 weeks of gestation. DR and FPR coefficients were calculated for 4 levels of risk as cut-off points for screening model 1, based on MA, NT, and first trimester biochemistry, as well as for screening model 2, based on MA, NT, first trimester biochemistry and NB.
Results: There were 5708 normal cases, 71 cases of trisomy 21 and 35 cases of other chromosomal defects. NB was absent in 46 (64.8%) cases and present in 25 (35.3%) cases of trisomy 21, comparing to present NB in 5463 (95.7%) and absent in 245 (4.3%) of normal cases.
Conclusions: First-semester screening with additional NB assessment significantly increases the detection rate for trisomy 21 and decreases the rate of false-positive results. Adding NB evaluation at the risk level of 1:50 causes only a small increase in detection rate. Invasive procedures should be performed in that group regardless NB assessment.

Abstract

 Objectives: Trisomy 21 is one of the most common chromosomal defects diagnosed prenatally. Screening for Down syndrome is based on maternal age, measurement of crown-rump length, nuchal translucency and fetal heart rate, together with free β-hCG and PAPP-A at 11 to 13 + 6 weeks. Introduction of additional ultrasound marker of trisomy 21 (evaluation of the nasal bone) may result in increased DR and decreased invasive diagnostic testing rates (FPR).
Material and methods: Ultrasound scan with NB evaluation was performed in 5814 fetuses during routine screening for chromosomal defects at 11 to 13 + 6 weeks of gestation. DR and FPR coefficients were calculated for 4 levels of risk as cut-off points for screening model 1, based on MA, NT, and first trimester biochemistry, as well as for screening model 2, based on MA, NT, first trimester biochemistry and NB.
Results: There were 5708 normal cases, 71 cases of trisomy 21 and 35 cases of other chromosomal defects. NB was absent in 46 (64.8%) cases and present in 25 (35.3%) cases of trisomy 21, comparing to present NB in 5463 (95.7%) and absent in 245 (4.3%) of normal cases.
Conclusions: First-semester screening with additional NB assessment significantly increases the detection rate for trisomy 21 and decreases the rate of false-positive results. Adding NB evaluation at the risk level of 1:50 causes only a small increase in detection rate. Invasive procedures should be performed in that group regardless NB assessment.

Get Citation

Keywords

nasal bone; chromosomal defects; screening for trisomy 21;

About this article
Title

Nasal bone in screening for T21 at 11–13 + 6 weeks of gestation — a multicenter study

Journal

Ginekologia Polska

Issue

Vol 87, No 11 (2016)

Pages

751-754

Published online

2016-11-30

DOI

10.5603/GP.2016.0082

Pubmed

27958633

Bibliographic record

Ginekol Pol 2016;87(11):751-754.

Keywords

nasal bone
chromosomal defects
screening for trisomy 21

Authors

Bartosz Czuba
Dawid Serafin
Piotr Węgrzyn
Wojciech Cnota
Mariusz Dubiel
Marek Mączka
Dariusz Zarotyński
Aleksandra Ruci
Mirosław Wielgoś
Krzysztof Sodowski
Dariusz Borowski

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