Correct estimation of parameters for ultrasound nuchal translucency screening.

Johnson, S. (1996). Down’s syndrome screening in the UK, Lancet, 347, 906–907. Pandya, P.P., Snijders, R.J.M., Johnson, S.P., de Loudes Brizot, M., Nicolaides, K.H. (1995). Screening for fetal trisomies by maternal age and fetal nuchal translucency thickness at 10 to 14 weeks of gestation, Br. J. Obstet. Gynaecol., 102, 957–962. Schuchter, K., Wald, N.J., Hackshaw, A.K., Hafner, E., Liebhardt, E. (1998). The distribution of nuchal translucency at 10–13 weeks of pregnancy, Prenat. Diagn., 18, 281–286. Wald, N.J., George, L., Smith, D., Densem, J.W., Petterson, K. (1996). On behalf of the International Prenatal Screening Research Group. Serum screening for Down’s syndrome between 8 and 14 weeks of pregnancy, Br. J. Obstet. Gynaecol., 103, 407– 412. Wald, N.J., Hackshaw, A.K. (1997). Combining ultrasound and biochemistry in first-trimester screening for Down’s syndrome, Prenat. Diagn., 17, 821–829. Wald, N.J., Kennard, A., Hackshaw, A., McGuire, A. (1997). Antenatal screening for Down’s syndrome, J. Med. Screren, 4, 181–246. Wald, N.J., Stone, R., Cuckle, H.S., Grudzinskas, J.G., Barkai, G., Brambati, B., Teisner, B., Fuhrmann, W. (1992). First trimester concentrations of PAPP-A and placental protein 14 in Down’s syndrome, BMJ, 305, 28.