Journal Mobile Options
Table of Contents
Vol. 22, No. 6, 2007
Issue release date: October 2007
Fetal Diagn Ther 2007;22:401–404
(DOI:10.1159/000106342)

Nuchal Translucency Measurements for First-Trimester Screening: The ‘Price’ of Inaccuracy

Evans M.I. · Van Decruyes H. · Nicolaides K.H.
aFetal Medicine Foundation of America, Comprehensive Genetics, Mt. Sinai School of Medicine, New York, N.Y., USA; bFetal Medicine Foundation, London, United Kingdom

Individual Users: Register with Karger Login Information

Please create your User ID & Password





Contact Information











I have read the Karger Terms and Conditions and agree.

To view the fulltext, please log in

To view the pdf, please log in

Abstract

Objective: First-trimester aneuploidy screening is in transition from the phase of ‘development’ to that of ‘diffusion.’ As with all other technologies, there is risk of diminished performance until newer centers are well experienced. Typically, inexperienced sonographers under-measure nuchal translucency (NT), and experience, training and continual monitoring of data are needed to ensure that measurements do not deviate. Here we assess the impact of systematic under-measurement on abnormality detection. Study Design: Actual NT measurements from 13,887 normal fetuses, 82 with trisomy 21 (T21) and 61 with other abnormalities (OA) with birth outcome data were mathematically modified to show either a 25% or 0.5-mm decrease in measurement. The impact upon sensitivity and screen-positive rates were assessed. Results: Reducing the NT measurements of T21 and OA cases lowers the sensitivity from 81.7 and 70.5%, respectively, to 67.1 and 62.3% (p < 0.01). If normals are correspondingly lowered, then the screen-positive rates are reduced from 6.9 to 2.0 and 2.5%. To maintain the same screen-positive rates and sensitivity, the risk threshold would have to be increased from 1/300 to 1/556. Conclusion: Minor inaccuracies in NT measurements as small as 25% or 0.5 mm will have very significant negative impacts upon abnormality detection, reducing detection rates by 18% (81.7 to 67.1%). Just as it is completely accepted that laboratory measurements require standardization and quality assurance, NT measurements, because they are used in an algorithm, need to be treated with the same rigor. That way the published data from centers that have developed such screening can be applied by other operators at other sites when counseling their patients.



Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

References

  1. Hyett J, Nicolaides KH: First trimester ultrasound screening with nuchal translucency; in Evans MI, Johnson MP, Yaron Y, Drugan A (eds): Prenatal Diagnosis. New York, McGraw-Hill, 2006, pp 289–308.
  2. Snijders RJ, Thom EA, Zachary JM, Platt LD, Greene N, Jackson LG, et al: First-trimester trisomy screening: nuchal translucency measurement training and quality assurance to correct and unify technique. Ultrasound Obstet Gynecol 2002;19:353–359.
  3. Snijders RJM, Noble P, Sebire N, Souka A, Nicolaides KH: UK multicentre project on assessment of risk of trisomy 21 by maternal age and fetal nuchal translucency thickness at 10–14 weeks of gestation. Lancet 1998;351:343–346.
  4. Monni G, Zoppi MA, Ibba RM, Floris M: Results of measurement of nuchal translucency before and after training. Lancet 1997;350:1631.
  5. Cicero S, Bindra R, Rembouskos G, Spencer K, Nicolaides KH: Integrated ultrasound and biochemical screening for trisomy 21 at 11 to 14 weeks. Prenat Diagn 2003;23:306–310.
  6. Avgidou K, Papageorghiou A, Bindra R, Spencer K, Nicolaides KH: Prospective first trimester screening for trisomy 21 in 30,564 pregnancies. Am J Obstet Gynecol 2005;192:1761–1767.
  7. Nicolaides KH, Spencer K, Avgidou K, Faiola S, Falcon O: Multicenter study of first-trimester screening for trisomy 21 in 75,821 pregnancies: results and estimation of the potential impact of individual risk-orientated two-stage first-trimester screening. Ultrasound Obstet Gynecol 2005;25:221–226.
  8. Evans MI, Hallahan TW, Krantz D, Galen RS: Meta-analysis of first trimester Down Syndrome screening studies: free beta hCG significantly outperforms intact hCG in a multi-marker protocol. Am J Obstet Gynecol (in press).
  9. Bewley S, Roberts LJ, Mackinson AM, Rodeck C: First trimester fetal nuchal translucency: problems with screening the general population. 2. Br J Obstet Gynecol 1995;102:386–388.
  10. Kornman LH, Morssink LP, Beekhuis JR, DeWolf BTHM, Heringa MP, Mantingh A: Nuchal translucency cannot be used as a screening test for chromosomal abnormalities in the first trimester of pregnancy in a routine ultrasound practice. Prenat Diagn 1996;16:797–805.
  11. Haddow JE, Palomaki GE, Knight GJ, Williams J, Miller WA, Johnson A: Screening of maternal serum for fetal Down’s syndrome in the first trimester. N Engl J Med 1998;338:955–961.
  12. Evans MI, Galen RS, Drugan A: Biochemical screening; in Evans MI, Johnson MP, Yaron Y, Drugan A (eds): Prenatal Diagnosis. New York, McGraw-Hill, 2006, pp 277–288.
  13. Wapner R, Thom E, Simpson JL, Pergament E, Silver R, Filkins K, et al: First trimester maternal serum biochemistry and fetal nuchal translucency screening (BUN) study group. First trimester screening for trisomies 21 and 18. N Engl J Med 2003;349:1405–1413.
  14. Malone FD, Canick JA, Ball RH, Nyberg DA, Comstock CH, Bukowski R, Berkowitz RL, Gross SJ, Dugoff L, Craigo SD, Timor-Tritsch IE, Carr SR, Wolfe HM, Dukes K, Bianchi DW, Rudnicka AR, Hackshaw AK, Lambert-Messerlian G, Wald NJ, D’Alton ME: First-trimester or second-trimester screening, or both, for Down’s syndrome. N Engl J Med 2005;353:2001–2011.
  15. Cohen AB, Hanft RS: Technology in American Health Care. Ann Arbor, University of Michigan Press, 2004.
  16. Cicero S, Curcio P, Papageorghious A, Sonek J, Nicolaides KH: Absence of nasal bone in fetuses with Trisomy 21 at 11–14 weeks of gestation: an observational study. Lancet 2001;358:1665–1667.
  17. Cicero S, Spencer K, Avgidou K, Faiola S, Nicolaides KH: Maternal serum biochemistry at 11–13 + 6 weeks in relation to the presence or absence of the fetal nasal bone on ultrasonography in chromosomally abnormal fetuses: an updated analysis of integrated ultrasound and biochemical screening. Prenat Diagn 2005;25:977–983.
  18. Falcon O, Auer M, Gerovassili A, Spencer K, Nicolaides KH: Screening for trisomy 21 tricuspid regurgitation, nuchal translucency and maternal serum free β hCG and PAPP-A at 11 + 0 to 13 + 6 weeks. Ultrasound Obstet Gynecol 2006;27:151–155.
  19. Gyselaers WJ, Vereecken AJ, Van Herck EJ, Straetmans DP, de Jonge ET, Ombelet WU, Nijhuis JG: Audit on nuchal translucency thickness measurements in Flanders, Belgium: a plea for methodological standardization. Ultrasound Obstet Gynecol 2004;24:511–515.


Pay-per-View Options
Direct payment This item at the regular price: USD 33.00
Payment from account With a Karger Pay-per-View account (down payment USD 150) you profit from a special rate for this and other single items.
This item at the discounted price: USD 23.00