• 1
    Wald NJ, Cuckle HS. Biochemical screening. In: BrockDJH, RodeckC, Ferguson-SmithMA, editors. Prenatal Diagnosis and Screening. Edinburgh : Churchill Livingstone, 1992: 563577.
  • 2
    Crossley JA, Aitken DA, Berry E, Connor JM. Impact of a regional screening programme using maternal serum alpha-fetoprotein (AFP) and human chorionic gonadotrophin hCG) on the birth incidence of Down's syndrome in the west of Scotland. J Med Screening 1994; 1: 180183.
  • 3
    Spencer K, Carpenter P. Prospective study of prenatal screening for Down's syndrome with free β human chorionic gonadotrophin. BMJ 1993; 307: 764769.
  • 4
    Macri JN, Spencer K, Carver K et al. Maternal serum free βhCG screening: results of studies including 480 cases of Down syndrome. PrenatDiagn 1994; 14: 97103.
  • 5
    Haddow JE, Palomaki GE, Knight GJ et al. Prenatal screening for Down's syndrome with the use of maternal serum markers. N Engl J Med 1992; 327: 588593.
  • 6
    Wald NJ, Kennard A, Densem JW, Cuckle HS, Chard T, Butler L. Antenatal maternal serum screening for Down's syndrome: results of a demonstration project. BMJ 1992; 305: 391394.
  • 7
    Goodburn SF, Yates JRW, Raggatt PR et al. Second trimester maternal serum screening using alpha-fetoprotein, human chorionic gonadotrophin and unconjugated oestriol: experience of a regional programme, PrenatDiagn 1994; 14: 391402.
  • 8
    Cuckle HS, Wald NJ, Barkai G et al. First trimester biochemical screening for Down syndrome. Lancet 1988; 2: 851852.
  • 9
    Brock DJH, Barron L, Holloway S, Listen WA, Hillier SG, Seppala M. First trimester maternal serum biochemical indicators in Down syndrome. Prenat Diagn 1990; 10: 245251.
  • 10
    Wenger, D, Miny, P, Holzgreve, W, Furhmann, W, Altland, K. First trimester maternal serum a-fetoprotein screening for Down syndrome and other aneuploidies. Am J Med Genet Suppl 1990; 7: 8990.
  • 11
    Crandall BF, Golbus MS, Goldberg JD, Matsumoto M. First trimester maternal serum unconjugated oestriol and alpha-fetoprotein in fetal Down's syndrome. Prenat Diagn 1991; 11: 377380.
  • 12
    Aitken DA, McCaw G, Crossley JA et al. First trimester biochemical screening for fetal chromosome abnormalities and neural tube defects. Prenat Diagn 1993; 13: 681689.
  • 13
    Spencer K, Aitken DA, Crossley JA et al. First trimester biochemical screening for trisomy 21: the role of free beta hCG, alpha fetoprotein and pregnancy associated plasma protein A. Ann Clin Biochem 1994; 31:447454.
  • 14
    Wald NJ, George L, Smith D, Densem JW, Petterson K. Serum screening for Down's syndrome between 8 and 14 weeks of pregnancy. Br J Obstet Gynaecol 1996; 103: 407412.
  • 15
    Macri JN, Spencer K, Aitken D et al. First trimester free βhCG screening for Down's syndrome. Prenat Diagn 1993; 13: 557562.
  • 16
    Spencer K, Macri JN, Aitken DA, Connor JM. Free βhCG is a first trimester marker for fetal trisomy. Lancet 1992; 339: 1480.
  • 17
    Macintosh MCM, Lles R, Teisner B et al. Maternal serum human chorionic gonadotrophin and pregnancy-associated plasma protein A, markers for fetal Down syndrome at 8–14 weeks. Prenat Diagn 1994; 14: 203208.
  • 18
    Brambati B, MacIntosh MCM, Teisner B et al. Low maternal serum levels of pregnancy associated plasma protein A (PAPP-A) in the first trimester in association with abnormal fetal karyotype. Br J Obstet Gynaecol 1993; 100: 324326.
  • 19
    Aitken DA, Wallace EM, Crossley JA et al. Dimeric inhibin A as a marker for Down's syndrome in early pregnancy. N Eng J Med 1996; 334: 2311236.
  • 20
    Berry E, Aitken DA, Crossley JA, Macri JN, Connor JM. Analysis of maternal serum alpha-fetoprotein and free beta human chorionic gonadotrophin in the first trimester: implications for Down's syndrome screening. Prenat Diagn 1995; 15: 555565.
  • 21
    Crossley JA, Aitken DA, Connor JM. Prenatal screening for chromosome abnormalities using maternal serum chorionic gonadotrophin, alphafetoprotein and age. PrenatDiagn 1991; 11: 83101.
  • 22
    Hook EB, Cross PK, Jackson L, Pergament E, Brambati B. Maternal age-specific rates of 47, +21 and other cytogenetic abnormalities diagnosed in the first trimester of pregnancy in chorionic villus biopsy specimens: comparisons with rate expected from observations at amniocentesis. Am J Hum Genet 1988; 42: 797807.
  • 23
    Aitken DA, Crossley JA. Prenatal screening—biochemical. In: WhittleMJ, ConnorJM, editors. Prenatal Diagnosis in Obstetric Practice. Oxford : Blackwell Science, 1995: 1229.
  • 24
    Zeitune M, Aitken DA, Crossley JA, Yates JR, Cooke A, Ferguson-Smith MA. Estimating the risk of a fetal autosomal trisomy at mid-trimester using maternal serum alpha-fetoprotein and age: a retrospective study of 142 pregnancies. Prenat Diagn 1991; 11: 847857.
  • 25
    Report of UK Collaborative Study on Alpha-fetoprotein in Relation to Neural-tube Defects. Maternal serum alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy. Lancet 1977; 1: 13231332.
  • 26
    Wald NJ, Hackshaw A, Stone R, Densem J. Serum alpha-fetoprotein and neural tube defects in the first trimester of pregnancy. Prenat Diagn 1993; 13: 10471050.
  • 27
    Wald NJ, Stone R, Cuckle HS, et al. First trimester concentrations of pregnancy associated plasma protein A and placental protein 14 in Down's syndrome. BMJ 1992; 305: 28.
  • 28
    Cuckle HS, Lilford RJ, Teisner B, Holding S, Chard T, Grudzinskas JG. Pregnancy associated plasma protein A in Down's syndrome. BMJ 1992; 305: 425.
  • 29
    Aitken DA, McKinnon D, Crossley JA et al. Changes in the maternal serum concentrations of PAPP-A and SP-1 in Down's syndrome pregnancies between the first and second trimesters. Proceedings of the ACB National Meeting; Birmingham; Apr 1993; Abstract B7. London : Association of Clinical Biochemists, 1993: 72.
  • 30
    Savoldclli G, Binkert F, Achermann J, Schmid W. Ultrasound screening for chromosomal anomalies in the first trimester of pregnancy. Prenat Diagn 1993; 13: 513518.
  • 31
    Brizot ML, Snijders RJM, Butler J, Bersinger NA, Nicolaides KH. Maternal serum βhCG and fetal nuchal translucency thickness for the prediction of fetal trisomies in the first trimester of pregnancy. Br J Obstet Gynaecol 1995; 102: 127132.
  • 32
    Snijders RJM, Pandya P, Brizot ML, Nicolaides KH. First trimester fetal nuchal translucency. In: SnijdersRJM, NicolaidesKH, editors. Ultrasound Markers far Fetal Chromosomal Defects. New York : Parthenon, 1996: 121149.
  • 33
    Krantz DA, Larsen JW, Buchanan PD, Macri JN. First-trimestcr Down syndrome screening: free β-human chorionic gonadotrophin and pregnancy associated plasma protein A. Am J Obstet Gynecol 1996; 174: 612616.