αlpha is based on the following references:

1 . Report of UK Collaborative Study on Alpha-fetoprotein in relation to neural tube defects (1977)


Maternal serum alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy. The lancet June, 1323-1332

9 . Screening for Down's syndrome (1990)


Cuckle HS, Wald NJ

In: Lilford RJ (Ed). Prenatal Diagnosis and Prognosis. 67-92. Butterworth

18 . Detection of pregnancies with trisomy 18 in screening programmes for Down's syndrome (1995)


Hackshaw AK, Kennard A, Wald NJ

J Med Screen 2, 228-229

19 . Risk-based prenatal screening for trisomy 18 using alpha-fetoprotein, unconjugated estriol and human chorionic gonadotropin (1995)


Palomaki GE, Haddow JE, Knight GJ, Wald NJ et al

Prenat Diagn 15, 713-723

29 . Antenatal Screening for Down’s syndrome (1997)


Wald NJ, Kennard A, Hackshaw A, McGuire A

J Med Screen 4, 181-246

30 . Empirical validation of risk screening for Down's syndrome (1996)


Wald NJ, Hackshaw AK, Huttly W, Kennard A

J Med Screen 3, 185-187

35 . Fetal loss in Down syndrome pregnancies (1999)


Morris JK, Wald NJ, Watt HC

Prenat Diagn 19, 142-145

36 . Screening for trisomy 18 by fetal nuchal translucency and maternal serum free β-hCG and PAPP-A at 10-14 weeks of gestation (1999)


Tul N, Spencer K, Noble P, Chan C, Nicolaides K

Prenat Diagn 19, 1035-1042

37 . Validation of risk estimation using the quadruple test in prenatal screening for Down syndrome (1999)


Wald NJ, Huttly WJ.

Prenat Diagn 19, 1083-1084

38 . Integrated screening for Down's syndrome based on tests performed during the first and second trimesters (1999)


Wald NJ, Watt HC, Hackshaw AK

N Eng J Med 341, 461-467

40 . Neural tube defects (2000)


Wald N

In: Wald N, Leck I (Eds). Antenatal and neonatal screening. Chapter 3, 61-84 Oxford University Press

41 . Assay precision of serum α fetoprotein in antenatal screening for neural tube defects and Down's syndrome (2000)


Wald NJ, Hackshaw AK, George LM

J Med Screen 7, 74-77

42 . Revised distribution parameters for serum markers for trisomy 18 (2005)


Hackshaw AK, Wald NJ

J Med Screen 7, 215

59 . Correction to SURUSS report (2006)


Wald NJ, Rodeck C, Hackshaw AK, Walters J, Chitty L, Mackinson AM, Bestwick JP

J Med Screen 13, 51-52

66 . Maternal serum invasive trophoblast antigen (ITA) in first trimester trisomy 18 pregnancies (2005)


Palomaki G, Knight G, Neveux L, Pandian R, Haddow J

Poster 2794 presented at The American Society for Human Genetics Annual Meeting, 2004, Toronto Canada.

73 . Recent advances in screening for neural tube defects and Down’s syndrome (1987)


Wald NJ and Cuckle HS

Bailliere’s Clinical Obstetrics and Gynaecology 1, 649-676

78 . Estimating an individual's risk of having a fetus with open spina bifida and the value of repeat alpha fetoprotein testing. Fourth Report of the U.K. Collaborative Study on Alpha fetoprotein in Relation to Neural Tube Defects (1982)


NJ Wald, HS Cuckle

J Epid Comm Hlth 36, 87 95

91 . Maternal illness and drug use in pregnancy (1992)


JM Elwood, J Little and JH Elwood

In JM Elwood, J Little and JH Elwood (Eds) Epidemiology and control of neural tube defects  Oxford University Press

93 . The use of free beta-hCG in antenatal screening for Down's syndrome (1993)


Wald NJ, Densem J, Stone R, Cheng

Br J Obstet Gynaecol 100 550-557

94 . Prediction of early intermediate and late pre-eclampsia from maternal factors, biophysical and biochemical markers at 11-13 weeks (2011)


Akolekar R, Syngelaki A, Sarquis R, Zvanca M, Nicolaides KH.

Prenat Diagn 31 66-74

95 . Competing risks model in early screening for preeclampsia by biophysical and biochemical markers (2013)


Akolekar R, Syngelaki A, Poon L, Wright D, Nicolaides KH.

Fetal Diagn Ther 33 8-15

96 . Epidemiological clues to the causation of neural tube defects.


Leck I

In Dobbing J (Ed) Prevention of Spina Bifida and other Neural Tube Defects, 155-182 Academic Press, London, 1983

108 . Pregnancy Associated Plasma Protein-A Truncation Limits in Antenatal Screening for Trisomy 18 (2016)


Bestwick JP, Huttly WJ, Wald NJ,

Submitted for publication to Journal of Medical Screening

110 . DNA sequencing of maternal plasma to detect Down syndrome: an international clinical validation study. (2011)


Palomaki GE, Kloza EM, Lambert-Messerlian GM et al

Genet Med. 2011 Nov;13(11):913-20