Document Detail

Combining nuchal translucency and serum markers in prenatal screening for Down syndrome in twin pregnancies.
MedLine Citation:
PMID:  12868090     Owner:  NLM     Status:  MEDLINE    
A method is described to combine the ultrasound marker nuchal translucency (NT) with serum markers so that they can be used together in prenatal screening for Down syndrome in twin pregnancies. For monochorionic twin pregnancies (taken as monozygous), the two fetus-specific NT measurements are averaged before risk is calculated and before the contribution of the serum markers is incorporated. For dichorionic twin pregnancies (taken as dizygous), the risk for each fetus based on the individual NT measurements is calculated, the two fetus-specific risks are added together, and then the contribution of the serum markers is incorporated. In this way, all the screening markers can be used in combination to produce a pregnancy-specific "pseudo-risk", rather than a fetus-specific pseudo-risk. We refer to pseudo-risk because in the absence of sufficient data on the screening markers in affected twin pregnancies, a true risk estimate cannot be calculated. Tentative estimates are given of screening performance in twins using NT, the combined test (NT with first-trimester serum markers), and the integrated test (NT with first- and second-trimester serum markers), all interpreted with maternal age.
Nicholas J Wald; Simon Rish; Allan K Hackshaw
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Prenatal diagnosis     Volume:  23     ISSN:  0197-3851     ISO Abbreviation:  Prenat. Diagn.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-17     Completed Date:  2003-12-04     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  8106540     Medline TA:  Prenat Diagn     Country:  England    
Other Details:
Languages:  eng     Pagination:  588-92     Citation Subset:  IM    
Copyright Information:
Copyright 2003 John Wiley & Sons, Ltd.
Wolfson Institute of Preventive Medicine, Bart's and the London School of Medicine and Dentistry, Charterhouse Square, London, UK.
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MeSH Terms
Biological Markers / blood
Chorionic Gonadotropin, beta Subunit, Human / blood
Down Syndrome / blood,  diagnosis*,  etiology*,  ultrasonography
Neck / embryology,  ultrasonography
Pregnancy Trimesters
Pregnancy-Associated Plasma Protein-A / metabolism
Prenatal Diagnosis*
Risk Factors
Ultrasonography, Prenatal
alpha-Fetoproteins / metabolism
Reg. No./Substance:
0/Biological Markers; 0/Chorionic Gonadotropin, beta Subunit, Human; 0/alpha-Fetoproteins; EC 3.4.24.-/Pregnancy-Associated Plasma Protein-A

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