| 1. | Boneva RS, Botto LD, Moore CA, et al. Mortality associated with congenital heart defects in the United States:trends and racial disparities. 1979-1997 Circulation, 2001, 103(19):2376-2381. | 
				                                                        
				                                                            
				                                                                | 2. | Nicolaides KH. The 11-13+6 weeks scan. Fetal Med Foun-dation, 2004, 1(18):71-88. | 
				                                                        
				                                                            
				                                                                | 3. | 唐英, 劉關鍵, 楊太珠. 孕早期超聲篩查胎兒結構畸形的循證病案討論. 中國循證醫學雜志, 2009, 9(6):705-708. | 
				                                                        
				                                                            
				                                                                | 4. | Souka AP, Krampl E, Bakalis S, et al. Outcome of pregnancy in chromosomally normal fetuses with increased nuchal translucency in the first trimester. Ultrasound Obstet Gynecol, 2001, 18(1):9-17. | 
				                                                        
				                                                            
				                                                                | 5. | McAuliffe FM, Hornberger LK, Winsor S, et al. Fetal cardiac defects and increased nuchal translucency thickness:a prospective study. Am J Obstet Gynecol, 2004, 191(4):1486-1490. | 
				                                                        
				                                                            
				                                                                | 6. | Lopes LM, Brizot ML, Lopes MAB, et al. Structural and functional cardiac abnormalities identified prior to 16 weeks' gestation in fetuses with increased nuchal translucency. Ultrasound Obstet Gynecol, 2003, 22(5):470-478. | 
				                                                        
				                                                            
				                                                                | 7. | Schwarzler P, Carvalho JS, Senat MV, et al. Screening for fetal aneuploidies and fetal cardiac abnormalities by nuchal translucency thickness measurement at 10-14 weeks of gestation as part of routine antenatal care in an unselected population. Br Obstet Gynaecol, 106(10):1029-1034. | 
				                                                        
				                                                            
				                                                                | 8. | Hyett J, Perdu M, Sharland G, et al. Using fetal nuchal translucency to screen for major congenital cardiac defects at 10-14 weeks of gestation:population based cohort study. BMJ, 1999, 318(7176):81-85. | 
				                                                        
				                                                            
				                                                                | 9. | Nicolaides KH, Azar G, Snijders RJ, et al. Fetal nuchalo edema:associated malformations and chromosomal defects. Fetal Diagn Ther, 1992, 7(2):123-131. | 
				                                                        
				                                                            
				                                                                | 10. | Pandya PP, Snijders RJ, Johnson SP, et al. Screening for fetal trisomies by maternal age and fetal nuchal translucency thickness at 10 to 14 weeks of gestation. Br J Obstet Gynaecol, 1995, 102(12):957-962. | 
				                                                        
				                                                            
				                                                                | 11. | Berger A.. Science commentary:What is fetal nuchal translucency? BMJ, 1999, 318(7176):85. | 
				                                                        
				                                                            
				                                                                | 12. | Atzei A, Gajewska K, Huggon IC, et al. Relationship between nuchal translucency thickness and prevalence of major cardiac defects in fetuses with normal karyotype. Ultrasound Obstet Gynecol, 2005, 26(2):154-157. | 
				                                                        
				                                                            
				                                                                | 13. | Makrydimas G, Sotiriadis A, Ioannidis JP. Screening performance of first-trimester nuchal translucency for major cardiac defects:a meta-analysis. Am Obstet Gynecol, 2003, 189(5):1330-1335. | 
				                                                        
				                                                            
				                                                                | 14. | Muller1 M, Clur S, Timmerman1, et al. Nuchal translucency measurement and congenital heart defects:modest association in low-risk pregnancies. Prenat Diagn, 2007, 27(2):164-169. | 
				                                                        
				                                                            
				                                                                | 15. | Simpson LL, Malone FD, Bianchi DW, et al. Nuchal translucency and the risk of congenital heart disease. Obstet Gynecol, 2007, 109(2Pt 1):376-383. | 
				                                                        
				                                                            
				                                                                | 16. | Wald NJ, Morris JK, Walker K, et al. Prenatal screening for serious congenital heart defects using nuchal translucency:a meta-analysis. Prenat Diagn, 2008, 28(12):1094-1104. | 
				                                                        
				                                                            
				                                                                | 17. | Chasen ST, Skupski DW, McCullough LB, et al. Prenatal informed consent for sonogram:the time for first-trimester nuchal translucency has come. Ultrasound Med, 2001, 20(11):1147-1152. | 
				                                                        
				                                                            
				                                                                | 18. | Yagel S, Cohen SM, Messing B. First trimester fetal heart screening. Curr Opin Obstet Gynecol, 2007, 19(2):183-190. | 
				                                                        
				                                                            
				                                                                | 19. | Bronshtein M, Zimmer EZ, Blazer S. The utility of detailed first trimester ultrasound examination in abnormal fetal nuchal translucency. Prenat Diagn, 2008, 28(11):1037-1041. | 
				                                                        
				                                                            
				                                                                | 20. | Lee W, Allan L, Carvalho JS, et al. ISUOG consensus statement:what constitutes a fetal echocardiogram? Ultrasound Obstet Gynecol, 2008, 32(2):239-242. |