title: Increased fetal nuchal translucency at 11-14 weeks.
abstract: Nuchal translucency (NT) is the sonographic appearance of a subcutaneous collection of fluid behind the fetal neck. The measurement of fetal NT thickness at the 11-14-week scan has been combined with maternal age to provide an effective method of screening for trisomy 21; for an invasive testing rate of 5%, about 75% of trisomic pregnancies can be identified. When maternal serum free-beta human chorionic gonadotrophin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11-14 weeks are also taken into account, the detection rate of chromosomal defects is about 90%. Increased NT can also identify a high proportion of other chromosomal abnormalities and is associated with major defects of the heart and great arteries, and a wide range of skeletal dysplasias and genetic syndromes. In monochorionic twins, discordancy for increased NT is an early marker of twin-to-twin transfusion syndrome (TTTS). As with the introduction of any new technology into routine clinical practice, it is essential that those undertaking the 11-14-week scan are adequately trained and their results are subjected to rigorous audit.
authors: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, King's College London, UK. kypros@fetalmedicine.com
authors: Kypros H
authors: KH
authors: Nicolaides
authors: Victoria
authors: V
authors: Heath
authors: Simona
authors: S
authors: Cicero
mesh_terms: D015415:Biomarkers / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000378:metabolism*; D002869:Chromosome Aberrations; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008423:Maternal Age; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D011296:Prenatal Diagnosis / Q000379:methods; D014427:Twins; D016216:Ultrasonography, Prenatal
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A