1Wald NJ, Densem JW, Smith D, et al. Four-marker serum screening for Down's syndrome. J Prenat Diagn, 1994, 14(9):707.
2Wald NJ, George L, Smith D, et al. Serum screening for Down's syndrome between 8 and 14 weeks of pregnancy. Br J Obstet Gynecol, 1996, 103: 407.
3Muller F, Aegerter P, Boue A, et al. Prospective maternal serum human chorionic gonadotropin screening for the risk offetal chromosome a nomalies and of subsequent fetal and necnatal deaths J Prenat Diagn,1993,13(1):29.
5Bryant LD, Green JM, Newison J. Prenatal screening for Down's syndrome: Some psychosocial implications of a screening for all policy. J Public Health,2001,115(5):356.
2Rosano A, Smithells D,Cacciani L,et al. Time trends in neural tube defects prevalence in relation to preventive strategies: an international study[J].J Epidemiol Community Health. 1999, 53 (10):630.
3Cuckle HS. Prenatal screening and diagnosis of neural tube defects in England and Wales in 1985[J].Prenat Diagn,1989,9 (6):393.
4Limb CJ, Holmes LB.Anencephaly:changes in prenatal detection and birth status, 1972 through 1990[J].Am J Obstet Gynecol,1994,170:1333.
5Morrow RJ, McNay MB, Whittle MJ. Ultrasound detection of neural tube defects in patients with elevated maternal serum alpha-fetoprotein[J].Obstet Gynecol. 1991,78:1055.
6American college of obstetricians and gynecologists, committee on obstetric practice. Guidelines for diagnostic imaging during pregnancy[J].ACOG Comm Opin, 1995,158:1.
7U.K.Collaborative Study:Maternal serum-alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy. Report of U.K.collaborative study on alpha-fetoprotein in relation to neural-tube defects[J].Lancet,1977,1:1323.
8Ashwood ER. Evaluating health and maturation of the unborn:The role of the clinical laboratory[J]. Clin Cjem,1992,38:1523.
9Christopher Cunniff.American academy of pediatrics. Clinical Report[J].Pediatrics,2004,114(3):889.
10Bahado-Singh RO, Sutton-Riley J.Open neural tube and abdominal wall defect[J]. Obstet Gynecol Clin North Am,2004,31(4):857.
