• 1
    Spencer K, Souter V, Tul N, Snijders R, Nicolaides KH. A screening program for trisomy 21 at 10–14 weeks using fetal nuchal translucency, maternal serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein-A. Ultrasound Obstet Gynecol 1999; 13: 231237.
  • 2
    Bindra R, Heath V, Liao A, Spencer K, Nicolaides KH. One-stop clinic for assessment of risk for trisomy 21 at 11–14 weeks: a prospective study of 15 030 pregnancies. Ultrasound Obstet Gynecol 2002; 20: 219225.
  • 3
    Spencer K, Spencer CE, Power M, Dawson C, Nicolaides KH. Screening for chromosomal abnormalities in the first trimester using ultrasound and maternal serum biochemistry in a one-stop clinic: a review of three years prospective experience. BJOG 2003; 110: 281286.
  • 4
    Wald NJ, Kennard A, Hackshaw A, McGuire A. Antenatal screening for Down's syndrome. Health Technol Assess 1998; 2: 1112.
  • 5
    Cicero S, Curcio P, Papageorghiou 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: 16651667.
  • 6
    Matias A, Gomes C, Flack N, Montenegro N, Nicolaides KH. Screening for chromosomal abnormalities at 11–14 weeks: the role of ductus venosus blood flow. Ultrasound Obstet Gynecol 1998; 2: 380384.
  • 7
    Huggon IC, DeFigueiredo DB, Allan LD. Tricuspid regurgitation in the diagnosis of chromosomal anomalies in the fetus at 11–14 weeks of gestation. Heart 2003; 89: 10711073.
  • 8
    Snijders RJM, Sundberg K, Holzgreve W, Henry G, Nicolaides KH. Maternal age and gestation-specific risk for trisomy 21. Ultrasound Obstet Gynecol 1999; 13: 167170.
  • 9
    Otano L, Aiello H, Igarzabal L, Matayoshi T, Gadow EC. Association between first trimester absence of fetal nasal bone on ultrasound and Down syndrome. Prenat Diagn 2002; 22: 930932.
  • 10
    Zoppi MA, Ibba RM, Axinan C, Floris M, Manca F, Monni G. Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies. Prenat Diagn 2003; 23: 496500.
  • 11
    Orlandi F, Bilardo CM, Campogrande M, Krantz D, Hallahan T, Rossi C, Viora E. Measurement of nasal bone length at 11–14 weeks of pregnancy and its potential role in Down syndrome risk assessment. Ultrasound Obstet Gynecol 2003; 22: 3639.
  • 12
    Viora E, Masturzo B, Errante G, Sciarrone A, Bastonero S, Campogrande M. Ultrasound evaluation of fetal nasal bone at 11 to 14 weeks in a consecutive series of 1906 fetuses. Prenat Diagn 2003; 23: 784787.
  • 13
    Senat MV, Bernard JP, Boulvain M, Ville Y. Intra- and interoperator variability in fetal nasal bone assessment at 11–14 weeks of gestation. Ultrasound Obstet Gynecol 2003; 22: 138141.
  • 14
    Wong SF, Choi H, Ho LC. Nasal bone hypoplasia: is it a common finding amongst chromosomally normal fetuses of southern Chinese women? Gynecol Obstet Invest 2003; 56: 99101.
  • 15
    Cicero S, Longo D, Rembouskos G, Sacchini C, Nicolaides KH. Absent nasal bone at 11–14 weeks of gestation and chromosomal defects. Ultrasound Obstet Gynecol 2003; 22: 3135.
  • 16
    Cicero S, Rembouskos G, Vandecruys H, Hogg M, Nicolaides KH. Likelihood ratio for trisomy 21 in fetuses with absent nasal bone at the 11–14-week scan. Ultrasound Obstet Gynecol 2004; 23: 218223.
  • 17
    Antolin E, Comas C, Torrents M, Munoz A, Figueras F, Echevarria M, Cararach M, Carrera JM. The role of ductus venosus blood flow assessment in screening for chromosomal abnormalities at 10–16 weeks of gestation. Ultrasound Obstet Gynecol 2001; 17: 295300.
  • 18
    Mavrides E, Sairam S, Hollis B, Thilaganathan B. Screening for aneuploidy in the first trimester by assessment of blood flow in the ductus venosus. BJOG 2002; 109: 10151019.
  • 19
    Murta CG, Moron AF, Avila MA, Weiner CP. Application of ductus venosus Doppler velocimetry for the detection of fetal aneuploidy in the first trimester of pregnancy. Fetal Diagn Ther 2002; 1: 308314.
  • 20
    Zoppi MA, Putzolu M, Ibba RM, Floris M, Monni G. First-trimester ductus venosus velocimetry in relation to nuchal translucency thickness and fetal karyotype. Fetal Diagn Ther 2002; 17: 5257.
  • 21
    Borrell A, Martinez JM, Seres A, Borobio V, Cararach V, Fortuny A. Ductus venosus assessment at the time of nuchal translucency measurement in the detection of fetal aneuploidy. Prenat Diagn 2003; 23: 921926.
  • 22
    Tabor A, Philip J, Madsen M, Bang J, Obel EB, Norgaard-Pedersen B. Randomised controlled trial of genetic amniocentesis in 4,606 low-risk women. Lancet 1986; i: 12871293.
  • 23
    Smidt-Jensen S, Permin M, Philip J, Lundsteen C, Zachary JM, Fowler SE, Gruning K. Randomised comparison of amniocentesis and transabdominal and transcervical chorionic villus sampling. Lancet 1992; 340: 12381244.