Document Detail

First-trimester Down syndrome screening: component analytes and timing for optimal performance.
MedLine Citation:
PMID:  16104668     Owner:  NLM     Status:  MEDLINE    
The most effective first-trimester Down syndrome screening protocol in current use employs three independent markers: maternal serum levels of PAPP-A and free beta hCG, and measurement of fetal nuchal translucency (NT). Eleven weeks appears to be the optimum gestational age for performing first trimester DS risk assessment. Although the discrimination of free beta hCG improves with increasing gestational age and is greatest at 13 weeks, PAPP-A and NT perform optimally at 10 and 11 weeks, respectively. In addition to accurate pregnancy dating, first trimester screening performance is improved by using a consistent NT measurement technique, NT cut-offs adjusted for gestational age or crown-rump length, and possibly center- or operator-specific NT medians. Whether or not absence or presence of the nasal bone adds to screening accuracy is a matter of some debate. Finally, because enlarged NT has been associated with cardiac defects and other structural anomalies, even in euploid fetuses, its presence should prompt a targeted second trimester ultrasound examination.
Katharine D Wenstrom
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Seminars in perinatology     Volume:  29     ISSN:  0146-0005     ISO Abbreviation:  Semin. Perinatol.     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-08-17     Completed Date:  2005-12-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7801132     Medline TA:  Semin Perinatol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  195-202     Citation Subset:  IM    
Department of Obstetrics and Gynecology, The University of Alabama at Birmingham, Birmingham, AL 35233, USA.
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MeSH Terms
Down Syndrome / diagnosis*,  ultrasonography
Fetal Diseases / diagnosis*,  ultrasonography
Infant, Newborn
Nuchal Translucency Measurement / methods
Pregnancy Trimester, First*
Prenatal Diagnosis / methods*
Ultrasonography, Prenatal / methods

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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