1Wald NJ, Todeck C, Hackshaw AK, et al. First and sencond trimester antenatal screening for Down' s syndrome: the results of the Serum, Urine and Ultrasound Screening Study ( SURUSS ). Health Technol Assess ( Winch ), 2003,7:1-7.
2Gilbert RE, Augood C, Gupta R, et al. Screening for Down' s syndrome: effects,safety,and cost effectiveness of first and second trimester strategies. BMJ,2001,323:423-425.
3Weisz B, Pandya PP, David AL, et al. Ultrasound findings after screening for Down syndrome using the integrated test. Obstet Gynecol, 2007, 109: 1046- 1052.
4Wright DE, Bradbury I. Repeated measures screening for Down's Syndrome. BJOG, 2005,112:80-83.
5Eloranta ML, Heinonen S, Kirkinen P. Intrahepatic cholestasis of pregnancy has no effect on maternal serum second trimeter alpha- fetoprotein and HCG. Acta Obstet Gynecol Scand, 2000,79: 548-552.
6Debieve F, Bouckaert A, Hubinont C, et al. Multiple screening for fetal Down's syndrome with the classic triple test, dimeric inhibin A and untrasound. Gynecol Obstet Invest,2000,49:221-226.
7Bromley B, Lieberman E, Shipp TD, et al.The genetic sonogram: a method of risk assessment for Down syndrome in the second trimester. J Ultrasound Med,.2002,21 : 1087-1096.
8Chaoui R, Heling KS, Sarioglu N, et al. Aberrant right subclavian artery as a new eardie sign in second and third - trimester fetuses with Down syndrome. Am J Obstet Gynecol,2005,192:257-263.
9Cicero S, Curcio P, Papageorghiou A, et al. Absence of nasal bone in fetuses with trisomy 21 at 11 - 14 weeks gestation: an observational study. Lancet, 2001,358:1665-1667.
10Andonova S, Vazharova R, Dimitrova V, et al. Introduction of the QF-PCR analysis for the purposes of prenatal diagnosis in Bulgaria-estimation of applicability of 6 STR markers on chromosomes 21 and 18. Prenat Diagn, 2004,24:202-208.
8wald NJ,et al. First and second trimester antenatal screening for DownS syndrome: the results of the seram,urine and ultrasound screeningstudy (SURUSS)[J ] . Health Techol Assess,2003,7(11):1 -77.
9Catanzarite VA, Jelovesek FR. Computing applications in obsterics[J ]. Am J Obstet Gynecol ,1987,156:1049.
10Nicolaides KH. Nuchal translucency and other rst - trimester sono-graphic markers of chromosomal abnormalities[ J ]. Am J Obstet Gy-neco,2004,191(1):45 -67.