The Diagnostic Value of Combined Test for Trisomy 21 and 18 Screening in Over 35-years Old Pregnant Women in the Gestational Age of 9-14 Weeks

Document Type : Original Article (s)

Authors

1 Associate Professor, Department of Obstetrics and Gynecology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

2 assistatnt professor,Isfahan University of Medical Sciences, Isfahan, IRAN

Abstract

Background: Early diagnosis of congenital anomalies and termination at early pregnancy can prevent the birth of these children. The Step-wise sequential test has the most sensitivity in this regard; but because of the religious and legal rules in our country (the abortion must be done before 17 weeks of gestation or 19 weeks of LMP), it is better to use a test that is performed in first trimester and has high sensitivity rate; so the use of invasive procedures become less. We aimed to estimate the diagnosis value of combined test (free beta-hCG, nuchal translucency, and pregnancy-associated protein A) for trisomy 21 and 18 screening.Methods: In this cross sectional study, 380 pregnant women with the age of more than 35 years referred to Beheshti and Alzahra clinics (Isfahan, Iran) at the 9-14 weeks of gestation were enrolled. Combines test analysis was done with Alpha software and the sample population was divided to high- and low-risk portions for trisomy 21 and 18. The high risks went on amniocentesis and the other group followed after birth for detecting if there were any signs of syndromes manifestation.Findings: For trisomy 21 (Down's syndrome), the sensitivity of combined test was 100%, and the specificity was 96.4%, with a false positive rate of 3.5%. For trisomy 18, it was 75% for the sensitivity and 100% for the specificity, with a false positive rate of 0%.Conclusion: Regarding to high sensitivity and specificity of the combined test in our population compared to other societies, we can use this test with more confidence. So, diagnosing the maternal anomalies in early first trimester could be done and we could terminate pregnancies with proven trisomy 21 and 18 legally.

Keywords

References

  1. Canick JA, Wilkins-Haug L, Barss VA, Messerlian GM. Labratory issues related to maternal serum screening for Down syndrome [Online] 2012. Available from: URL: http://utdol.com/online/content/topic.do?topicKey=antenatl/12590&view
  2. Canick JA, Wilkins L, Barss VA, Messerlian GM, Farina A. First trimester and integrated screening for Down syndrome and trisomy 18 [Online] 2012. Available from: URL: http://www.uptodate.com/contents/first-trimester-combined-test-and-integrated-tests-for-screening-for-down-syndrome-and-trisomy-18.
  3. Orlandi F, Damiani G, Hallahan TW, Krantz DA, Macri JN. First-trimester screening for fetal aneuploidy: biochemistry and nuchal translucency. Ultrasound Obstet Gynecol 1997; 10(6): 381-6.
  4. Wright D, Spencer K, Kagan KK, Torring N, Petersen OB, Christou A, et al. First-trimester combined screening for trisomy 21 at 7-14 weeks' gestation. Ultrasound Obstet Gynecol 2010; 36(4): 404-11.
  5. Simpson JL. Genetic counseling and prenatal diagnosis. In: Gabbe SG, Niebyi JR, Simpson JL, editors. Obstetrics: normal and problem pregnancics. 5th ed. New York, NY: Churchil Livingston; 2007. p. 187-219.
  6. Hoffman B, Horsager R, Roberts S, Rogers V. Williams obstetrics. 23th ed. New York, NY: McGraw-Hill; 2011. p. 268.
  7. Schreinemachers DM, Cross PK, Hook EB. Rates of trisomies 21, 18, 13 and other chromosome abnormalities in about 20 000 prenatal studies compared with estimated rates in live births. Hum Genet 1982; 61(4): 318-24.
  8. Farndon PA, Kilby MD. Genetics, risks and genetic counseling. In: James DK, Steer PJ, Weiner CP, Gonik B, editors. High risk pregnancy. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2005.p. 43-63.
  9. Schneider AS, Mennuti MT, Zackai EH. High cesarean section rate in trisomy 18 births: a potential indication for late prenatal diagnosis. Am J Obstet Gynecol 1981; 140(4): 367-70.
  10. Schmidt P, Hormansdorfer C, Staboulidou I, Hillemanns P, Scharf A. Using "Degree of Extremeness" instead of "Multiples of Median" in first trimester risk assessment for Down syndrome-an improved method or just a gimmick in face of political motivations? Arch Gynecol Obstet 2008; 278(2): 119-24.
  11. Bower C, Rudy E, Ryan A, Callughan A, Quick J, Cosgrove P. Report of the birth defects registry of western Australia 1980-2009 [cited 2010 Dec]; Available from: URL: kemh.health.wa.gov.au/services/register.../2010_Annual_Report.pdf‎
  12. Pour Javad M, Dadgar S, Shakeri MT, Mahmoudi M. Evaluation of triple test results and determining the median of serum markers for early diagnosis of first-trimester congenital anomalies. Iran J Obstet Gynecol Infertil 2010; 13(1): 21-6.
  13. O'Leary P, Breheny N, Dickinson JE, Bower C, Goldblatt J, Hewitt B, et al. First-trimester combined screening for Down syndrome and other fetal anomalies. Obstet Gynecol 2006; 107(4): 869-76.
  14. Canick JA, Lambert-Messerlian GM, Palomaki GE, Neveux LM, Malone FD, Ball RH, et al. Comparison of serum markers in first-trimester down syndrome screening. Obstet Gynecol 2006; 108(5): 1192-9.
  15. Kagan KO, Anderson JM, Anwandter G, Neksasova K, Nicolaides KH. Screening for triploidy by the risk algorithms for trisomies 21, 18 and 13 at 11 weeks to 13 weeks and 6 days of gestation. Prenat Diagn 2008; 28(13): 1209-13.
  16. Kagan KO, Wright D, Valencia C, Maiz N, Nicolaides KH. Screening for trisomies 21, 18 and 13 by maternal age, fetal nuchal translucency, fetal heart rate, free beta-HCG and pregnancy-associated plasma protein-A. Hum Reprod 2008; 23(9): 1968-75.
  17. Wortelboer EJ, Koster MP, Stoutenbeek P, Elvers LH, Loeber JG, Visser GH, et al. First-trimester Down syndrome screening performance in the Dutch population; how to achieve further improvement? Prenat Diagn 2009; 29(6): 588-92.
  18. Leung TY, Chan LW, Leung TN, Fung TY, Sahota DS, Spencer K, et al. First-trimester combined screening for trisomy 21 in a predominantly Chinese population. Ultrasound Obstet Gynecol 2007; 29(1): 14-7.
Journal of Isfahan Medical School
Volume 31, Issue 231 - Serial Number 231
March and April 2013
Pages 400-407

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History

  • Receive Date: 17 April 2012
  • Revise Date: 01 November 2024
  • Accept Date: 06 April 2022

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