Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-16T08:32:29.975Z Has data issue: false hasContentIssue false

THE GENETIC SONOGRAM

Published online by Cambridge University Press:  05 August 2014

ICHCHHA MADAN
Affiliation:
Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Oakland University William Beaumont School of Medicine, Rochester, MI.
MARK REDMAN
Affiliation:
Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Oakland University William Beaumont School of Medicine, Rochester, MI.
RICHARD BRONSTEEN
Affiliation:
Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Oakland University William Beaumont School of Medicine, Rochester, MI.
RAY O BAHADO-SINGH
Affiliation:
Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Oakland University William Beaumont School of Medicine, Rochester, MI.
LUIS F GONCALVES*
Affiliation:
Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Oakland University William Beaumont School of Medicine, Rochester, MI. Department of Radiology, Division of Pediatric Radiology, Oakland University William Beaumont School of Medicine, Rochester, MI.
*
Luís F. Gonçalves, M.D., Professor of Obstetrics and Gynecology and Radiology, Co-Director, Division of Fetal Imaging, Oakland University William Beaumont School of Medicine, Rochester, MI. Email: luis.goncalves@beaumont.edu

Abstract

Image of the first page of this content. For PDF version, please use the ‘Save PDF’ preceeding this image.'
Type
Review Article
Copyright
Copyright © Cambridge University Press 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Reddy, UM, Abuhamad, AZ, Levine, D, Saade, GR, Fetal Imaging Workshop Invited Participants. Fetal imaging: executive summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop. J Ultrasound Med 2014; 33: 745–57.Google Scholar
2.Mason, G, Baillie, C. Counselling should be provided before parents are told of presence of ultrasonographic “soft markers” of fetal abnormality. BMJ 1997; 315: 189–90.Google Scholar
3.Watson, MS, Hall, S, Langford, K, Marteau, TM. Psychological impact of the detection of soft markers on routine ultrasound scanning: a pilot study investigating the modifying role of information. Prenat Diagn 2002; 22: 569–75.CrossRefGoogle ScholarPubMed
4.Society for Maternal-Fetal Medicine (SMFM), Fuchs KM. Isolated choroid plexus cysts: their implications and outcomes. Contemporary OB/GYN: ModernMedicine Network; 2013.Google Scholar
5.Moyer, K, Goldberg, JD. SMFM consult: isolated echogenic intracardiac focus. Contemporary OB/GYN August 1, 2013. http://contemporaryobgyn.modernmedicine.com/contemporary-obgyn/news/smfm-consult-isolated-echogenic-intracardiac-focus. Accessed on 7 December 2014.Google Scholar
6.Agathokleous, M, Chaveeva, P, Poon, LC, Kosinski, P, Nicolaides, KH. Meta-analysis of second-trimester markers for trisomy 21. Ultrasound Obstet Gynecol 2013; 41: 247–61.CrossRefGoogle ScholarPubMed
7.Benacerraf, BR, FrigolettoFD, Jr. FD, Jr., Laboda, LA. Sonographic diagnosis of Down syndrome in the second trimester. Am J Obstet Gynecol 1985; 153: 4952.Google Scholar
8.Benacerraf, BR, Gelman, R, FrigolettoFD, Jr. FD, Jr.Sonographic identification of second-trimester fetuses with Down's syndrome. New Engl J Med 1987; 317: 1371–6.CrossRefGoogle ScholarPubMed
9.Carlson, DE, Platt, LD. Ultrasound detection of genetic anomalies. J Reprod Med 1992; 37: 419–26.Google ScholarPubMed
10.Nicolaides, KH, Snijders, RJ, Gosden, CM, Berry, C, Campbell, S. Ultrasonographically detectable markers of fetal chromosomal abnormalities. Lancet 1992; 340: 704–7.Google Scholar
11.Vintzileos, AM, Campbell, WA, Rodis, JF, Guzman, ER, Smulian, JC, Knuppel, RA. The use of second-trimester genetic sonogram in guiding clinical management of patients at increased risk for fetal trisomy 21. Obstet Gynecol 1996; 87: 948–52.Google Scholar
12.DeVore, GR, Alfi, O. The use of color Doppler ultrasound to identify fetuses at increased risk for trisomy 21: an alternative for high-risk patients who decline genetic amniocentesis. Obstet Gynecol 1995; 85: 378–86.CrossRefGoogle ScholarPubMed
13.Bahado-Singh, RO, Mendilcioglu, I, Rowther, M, Choi, SJ, Oz, U, Yousefi, NFet al.Early genetic sonogram for Down syndrome detection. Am J Obstet Gynecol 2002; 187: 1235–8.CrossRefGoogle ScholarPubMed
14.Nyberg, DA, Luthy, DA, Resta, RG, Nyberg, BC, Williams, MA. Age-adjusted ultrasound risk assessment for fetal Down's syndrome during the second trimester: description of the method and analysis of 142 cases. Ultrasound Obstet Gynecol 1998; 12: 814.Google Scholar
15.Bromley, B, Shipp, T, Benacerraf, BR. Genetic sonogram scoring index: accuracy and clinical utility. J Ultrasound Med 1999; 18: 523–8; quiz 9–30.Google Scholar
16.Pinette, MG, Garrett, J, Salvo, A, Blackstone, J, Pinette, SG, Boutin, Net al.Normal midtrimester (17–20 weeks) genetic sonogram decreases amniocentesis rate in a high-risk population. J Ultrasound Med 2001; 20: 639–44.Google Scholar
17.Bromley, B, Lieberman, E, Shipp, TD, Benacerraf, BR. The genetic sonogram: a method of risk assessment for Down syndrome in the second trimester. J Ultrasound Med 2002; 21: 1087–96; quiz 97–8.Google Scholar
18.DeVore, GR. Is genetic ultrasound cost-effective? Semin Perinatol 2003; 27: 173–82.Google Scholar
19.Yeo, L, Vintzileos, AM. The use of genetic sonography to reduce the need for amniocentesis in women at high-risk for Down syndrome. Semin Perinatol 2003; 27: 152–9.Google Scholar
20.Benacerraf, BR. The role of the second trimester genetic sonogram in screening for fetal Down syndrome. Semin Perinatol 2005; 29: 386–94.Google Scholar
21.Benacerraf, BR, Neuberg, D, Bromley, B, FrigolettoFD, Jr. FD, Jr.Sonographic scoring index for prenatal detection of chromosomal abnormalities. J Ultrasound Med 1992; 11: 449–58.Google Scholar
22.Smith-Bindman, R, Hosmer, W, Feldstein, VA, Deeks, JJ, Goldberg, JD. Second-trimester ultrasound to detect fetuses with Down syndrome: a meta-analysis. JAMA 2001; 285: 1044–55.Google Scholar
23.Snijders, RJM, Nicolaides, KH. Ultrasound Markers for Fetal Chromosomal Defects. Carnforth, UK: Parthenon Publishing; 1996.Google Scholar
24.DeVore, GR. The genetic sonogram: its use in the detection of chromosomal abnormalities in fetuses of women of advanced maternal age. Prenat Diagn 2001; 21: 40–5.Google Scholar
25.Lauria, MR, Branch, MD, LaCroix, VH, Harris, RD, Baker, ER. Clinical impact of systematic genetic sonogram screening in a low-risk population. J Reprod Med 2007; 52: 359–64.Google Scholar
26.Malone, FD, Canick, JA, Ball, RH, Nyberg, DA, Comstock, CH, Bukowski, Ret al.First-trimester or second-trimester screening, or both, for Down's syndrome. New Engl J Med 2005; 353: 2001–11.CrossRefGoogle ScholarPubMed
27.American College of Obstetricians and Gynecologists Committee on Genetics. Committee opinion no. 545: noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol 2012; 120: 1532–4.Google Scholar
28.Driscoll, DA, Gross, SJ, Professional Practice Guidelines Committee. Screening for fetal aneuploidy and neural tube defects. Genet Med 2009; 11: 818–21.Google Scholar
29.Ibrahim, H, Newman, M. Ultrasound soft markers of chromosomal abnormalities; an ethical dilemma for obstetricians. Hum Reprod Genet 2005; 11: 25–7.Google Scholar
30.Shaffer, LG, Rosenfeld, JA, Dabell, MP, Coppinger, J, Bandholz, AM, Ellison, JWet al.Detection rates of clinically significant genomic alterations by microarray analysis for specific anomalies detected by ultrasound. Prenat Diagn 2012; 32: 986–95.Google Scholar
31.Wapner, RJ, Martin, CL, Levy, B, Ballif, BC, Eng, CM, Zachary, JMet al.Chromosomal microarray versus karyotyping for prenatal diagnosis. New Engl J Med 2012; 367: 2175–84.CrossRefGoogle ScholarPubMed
32.American College of Obstetricians and Gynecologists. ACOG practice bulletin no. 88, December 2007. Invasive prenatal testing for aneuploidy. Obstet Gynecol 2007; 110: 1459–67.CrossRefGoogle Scholar
33.Miguelez, J, De Lourdes Brizot, M, Liao, AW, De Carvalho, MH, Zugaib, M. Second-trimester soft markers: relation to first-trimester nuchal translucency in unaffected pregnancies. Ultrasound Obstet Gynecol 2012; 39: 274–8.Google Scholar
34.Cho, JY, Kim, KW, Lee, YH, Toi, A. Measurement of nuchal skin fold thickness in the second trimester: influence of imaging angle and fetal presentation. Ultrasound Obstet Gynecol 2005; 25: 253–7.CrossRefGoogle ScholarPubMed
35.Lee, PR, Won, HS, Chung, JY, Shin, HJ, Kim, A. The variables affecting nuchal skin-fold thickness in mid-trimester. Prenat Diagn 2003; 23: 60–4.Google Scholar
36.Nyberg, DA, Souter, VL, El-Bastawissi, A, Young, S, Luthhardt, F, Luthy, DA. Isolated sonographic markers for detection of fetal Down syndrome in the second trimester of pregnancy. J Ultrasound Med 2001; 20: 1053–63.Google Scholar
37.Aagaard-Tillery, KM, Malone, FD, Nyberg, DAet al.Role of second-trimester genetic sonography after Down syndrome screening. Obstet Gynecol 2009; 114: 1189–96.CrossRefGoogle ScholarPubMed
38.Jelliffe-Pawlowski, LL, Walton-Haynes, L, Currier, RJ. Identification of second trimester screen positive pregnancies at increased risk for congenital heart defects. Prenat Diagn 2009; 29: 570–7.Google Scholar
39.Maymon, R, Zimerman, AL, Weinraub, Z, Herman, A, Cuckle, H. Correlation between nuchal translucency and nuchal skin-fold measurements in Down syndrome and unaffected fetuses. Ultrasound Obstet Gynecol 2008; 32: 501–5.CrossRefGoogle ScholarPubMed
40.Bakker, M, Pajkrt, E, Mathijssen, IB, Bilardo, CM. Targeted ultrasound examination and DNA testing for Noonan syndrome, in fetuses with increased nuchal translucency and normal karyotype. Prenat Diagn 2011; 31: 833–40.Google Scholar
41.Houweling, AC, de Mooij, YM, van der Burgt, I, Yntema, HG, Lachmeijer, AM, Go, AT. Prenatal detection of Noonan syndrome by mutation analysis of the PTPN11 and the KRAS genes. Prenat Diagn 2010; 30: 284–6.Google Scholar
42.Zafar, HM, Ankola, A, Coleman, B. Ultrasound pitfalls and artifacts related to six common fetal findings. Ultrasound Q 2012; 28: 105–24.Google Scholar
43.Scioscia, AL, Pretorius, DH, Budorick, NE, Cahill, TC, Axelrod, FT, Leopold, GR. Second-trimester echogenic bowel and chromosomal abnormalities. Am J Obstet Gynecol 1992; 167: 889–94.Google Scholar
44.Benacerraf, BR, Chaudhury, AK. Echogenic fetal bowel in the third trimester associated with meconium ileus secondary to cystic fibrosis. A case report. J Reprod Med 1989; 34: 299300.Google Scholar
45.Hill, LM, Fries, J, Hecker, J, Grzybek, P. Second-trimester echogenic small bowel: an increased risk for adverse perinatal outcome. Prenat Diagn 1994; 14: 845–50.Google Scholar
46.Nyberg, DA, Dubinsky, T, Resta, RG, Mahony, BS, Hickok, DE, Luthy, DA. Echogenic fetal bowel during the second trimester: clinical importance. Radiology 1993; 188: 527–31.Google Scholar
47.Goetzinger, KR, Cahill, AG, Macones, GA, Odibo, AO. Echogenic bowel on second-trimester ultrasonography: evaluating the risk of adverse pregnancy outcome. Obstet Gynecol 2011; 117: 1341–8.CrossRefGoogle ScholarPubMed
48.Saha, E, Mullins, EW, Paramasivam, G, Kumar, S, Lakasing, L. Perinatal outcomes of fetal echogenic bowel. Prenat Diagn 2012; 32: 758–64.Google Scholar
49.Al-Kouatly, HB, Chasen, ST, Karam, AK, Ahner, R, Chervenak, FA. Factors associated with fetal demise in fetal echogenic bowel. Am J Obstet Gynecol 2001; 185: 1039–43.Google Scholar
50.Grignon, A, Dubois, J, Ouellet, MC, Garel, L, Oligny, LL, Potier, M. Echogenic dilated bowel loops before 21 weeks’ gestation: a new entity. AJR Am J Roentgenol 1997; 168: 833–7.Google Scholar
51.Sepulveda, W, Reid, R, Nicolaidis, P, Prendiville, O, Chapman, RS, Fisk, NM. Second-trimester echogenic bowel and intraamniotic bleeding: association between fetal bowel echogenicity and amniotic fluid spectrophotometry at 410 nm. Am J Obstet Gynecol 1996; 174: 839–42.Google Scholar
52.Society for Maternal-Fetal Medicine (SMFM), Odibo, A, Goetzinger, KR. Isolated echogenic bowel diagnosed on second-trimester ultrasound. Contemporary OB/GYN: ModernMedicine Network; 2011.Google Scholar
53.Mailath-Pokorny, M, Klein, K, Klebermass-Schrehof, K, Hachemian, N, Bettelheim, D. Are fetuses with isolated echogenic bowel at higher risk for an adverse pregnancy outcome? Experiences from a tertiary referral center. Prenat Diagn 2012; 32: 1295–9.CrossRefGoogle ScholarPubMed
54.Scotet, V, Dugueperoux, I, Audrezet, MP, Audebert-Bellanger, S, Muller, M, Blayau, Met al.Focus on cystic fibrosis and other disorders evidenced in fetuses with sonographic finding of echogenic bowel: 16-year report from Brittany, France. Am J Obstet Gynecol 2010; 203: 592 e1–6.CrossRefGoogle ScholarPubMed
55.Al-Kouatly, HB, Chasen, ST, Streltzoff, J, Chervenak, FA. The clinical significance of fetal echogenic bowel. Am J Obstet Gynecol 2001; 185: 1035–8.CrossRefGoogle ScholarPubMed
56.Carbone, JF, Tuuli, MG, Dicke, JM, Macones, GA, Odibo, AO. Revisiting the risk for aneuploidy in fetuses with isolated pyelectasis. Prenat Diagn 2011; 31: 566–70.Google Scholar
57.Benacerraf, BR, Mandell, J, Estroff, JA, Harlow, BL, FrigolettoFD, Jr. FD, Jr.Fetal pyelectasis: a possible association with Down syndrome. Obstet Gynecol 1990; 76: 5860.Google Scholar
58.Orzechowski, KM, Berghella, V. Isolated fetal pyelectasis and the risk of Down syndrome: a meta-analysis. Ultrasound Obstet 2013; 42: 615–21.Google Scholar
59.Society for Maternal-Fetal Medicine (SMFM), Norton, ME. Evaluation and management of isolated renal pelviectasis diagnosed on second trimester ultrasound. Contemporary OB/GYN: ModernMedicine Network; 2011.Google Scholar
60.Lee, RS, Cendron, M, Kinnamon, DD, Nguyen, HT. Antenatal hydronephrosis as a predictor of postnatal outcome: a meta-analysis. Pediatrics 2006; 118: 586–93.Google Scholar
61.van Lith, JM, Benacerraf, BR, Yagel, S. Current controversies in prenatal diagnosis 2: Down syndrome screening: is ultrasound better than cell-free nucleic acids in maternal blood? Prenat Diagn 2011; 31: 231–4.Google Scholar
62.Shipp, TD, Bromley, B, Mascola, M, Benacerraf, B. Variation in fetal femur length with respect to maternal race. J Ultrasound Med 2001; 20: 141–4.CrossRefGoogle ScholarPubMed
63.Weisz, B, David, AL, Chitty, L, Peebles, D, Pandya, P, Patel, Pet al.Association of isolated short femur in the mid-trimester fetus with perinatal outcome. Ultrasound Obstet Gynecol 2008; 31: 512–6.Google Scholar
64.Goetzinger, KR, Cahill, AG, Macones, GA, Odibo, AO. Isolated short femur length on second-trimester sonography: a marker for fetal growth restriction and other adverse perinatal outcomes. J Ultrasound Med 2012; 31: 1935–41.Google Scholar
65.Goncalves, L, Jeanty, P. Fetal biometry of skeletal dysplasias: a multicentric study. J Ultrasound Med 1994; 13: 977–85.Google Scholar
66.Schechter, AG, Fakhry, J, Shapiro, LR, Gewitz, MH. In utero thickening of the chordae tendinae. A cause of intracardiac echogenic foci. J Ultrasound Med 1987; 6: 691–5.Google Scholar
67.Wax, JR, Mather, J, Steinfeld, JD, Ingardia, CJ. Fetal intracardiac echogenic foci: current understanding and clinical significance. Obstet Gynecol Surv 2000; 55: 303–11.Google Scholar
68.Norton, ME. Follow-up of sonographically detected soft markers for fetal aneuploidy. Semin Perinatol 2013; 37: 365–9.Google Scholar
69.Bronsteen, R, Lee, W, Vettraino, IM, Huang, R, Comstock, CH. Second-trimester sonography and trisomy 18: the significance of isolated choroid plexus cysts after an examination that includes the fetal hands. J Ultrasound Med 2004; 23: 241–5.CrossRefGoogle ScholarPubMed
70.Ghidini, A, Strobelt, N, Locatelli, A, Mariani, E, Piccoli, MG, Vergani, P. Isolated fetal choroid plexus cysts: role of ultrasonography in establishment of the risk of trisomy 18. Am J Obstet Gynecol 2000; 182: 972–7.Google Scholar
71.Digiovanni, LM, Quinlan, MP, Verp, MS. Choroid plexus cysts: infant and early childhood developmental outcome. Obstet Gynecol 1997; 90: 191–4.Google Scholar
72.Bernier, FP, Crawford, SG, Dewey, D. Developmental outcome of children who had choroid plexus cysts detected prenatally. Prenat Diagn 2005; 25: 322–6.CrossRefGoogle ScholarPubMed
73.Yoder, PR, Sabbagha, RE, Gross, SJ, Zelop, CM. The second-trimester fetus with isolated choroid plexus cysts: a meta-analysis of risk of trisomies 18 and 21. Obstet Gynecol 1999; 93: 869–72.Google Scholar
74.Melchiorre, K, Bhide, A, Gika, AD, Pilu, G, Papageorghiou, AT. Counseling in isolated mild fetal ventriculomegaly. Ultrasound Obstet Gynecol 2009; 34: 212–24.Google Scholar
75.Beeghly, M, Ware, J, Soul, J, du Plessis, A, Khwaja, O, Senapati, GMet al.Neurodevelopmental outcome of fetuses referred for ventriculomegaly. Ultrasound Obstet Gynecol 2010; 35: 405–16.Google Scholar
76.Benacerraf, BR, Shipp, TD, Bromley, B, Levine, D. What does magnetic resonance imaging add to the prenatal sonographic diagnosis of ventriculomegaly? J Ultrasound Med 2007; 26: 1513–22.CrossRefGoogle Scholar
77.Salomon, LJ, Ouahba, J, Delezoide, AL, Vuillard, E, Oury, JF, Sebag, Get al.Third-trimester fetal MRI in isolated 10- to 12-mm ventriculomegaly: is it worth it? BJOG 2006; 113: 942–7.CrossRefGoogle ScholarPubMed
78.Bromley, B, Lieberman, E, Shipp, TD, Benacerraf, BR. Fetal nose bone length: a marker for Down syndrome in the second trimester. J Ultrasound Med 2002; 21: 1387–94.Google Scholar
79.Odibo, AO, Sehdev, HM, Stamilio, DM, Cahill, A, Dunn, L, Macones, GA. Defining nasal bone hypoplasia in second-trimester Down syndrome screening: does the use of multiples of the median improve screening efficacy? Am J Obstet Gynecol 2007; 197: 361 e1–4.Google Scholar
80.Cicero, S, Sonek, JD, McKenna, DS, Croom, CS, Johnson, L, Nicolaides, KH. Nasal bone hypoplasia in trisomy 21 at 15–22 weeks’ gestation. Ultrasound Obstet Gynecol 2003; 21: 15–8.CrossRefGoogle ScholarPubMed
81.Sonek, JD, Cicero, S, Neiger, R, Nicolaides, KH. Nasal bone assessment in prenatal screening for trisomy 21. Am J Obstet Gynecol 2006; 195: 1219–30.Google Scholar
82.Rosen, T, D’Alton, ME, Platt, LD, Wapner, R, Nuchal Translucency Oversight Committee, Maternal Fetal Medicine Foundation. First-trimester ultrasound assessment of the nasal bone to screen for aneuploidy. Obstet Gynecol 2007; 110: 399404.Google Scholar
83.Sonek, JD, McKenna, D, Webb, D, Croom, C, Nicolaides, K. Nasal bone length throughout gestation: normal ranges based on 3537 fetal ultrasound measurements. Ultrasound Obstet Gynecol 2003; 21: 152–5.Google Scholar
84.Kommerell, B. Verlagerung des Ösophagus durch eine abnorm verlaufende Arteria subclavia dextra (Arteria lusoria). Fortschr Geb Roentgenstr 1936; 54: 590–5.Google Scholar
85.Strauss, L. Congenital cardiac anomalies associated with mongolism. Trans Am Coll Cardiol 1954; 3: 214–21.Google Scholar
86.Goldstein, WB. Aberrant Right Subclavian Artery in Mongolism. Am J Roentgenol Radium Ther Nucl Med 1965; 95: 131–4.Google Scholar
87.Chaoui, R, Heling, KS, Sarioglu, N, Schwabe, M, Dankof, A, Bollmann, R. Aberrant right subclavian artery as a new cardiac sign in second- and third-trimester fetuses with Down syndrome. Am J Obstet Gynecol 2005; 192: 257–63.Google Scholar
88.Borenstein, M, Minekawa, R, Zidere, V, Nicolaides, KH, Allan, LD. Aberrant right subclavian artery at 16 to 23 + 6 weeks of gestation: a marker for chromosomal abnormality. Ultrasound Obstet Gynecol 2010; 36: 548–52.Google Scholar
89.Borenstein, M, Cavoretto, P, Allan, L, Huggon, I, Nicolaides, KH. Aberrant right subclavian artery at 11 + 0 to 13 + 6 weeks of gestation in chromosomally normal and abnormal fetuses. Ultrasound Obstet Gynecol 2008; 31: 20–4.Google Scholar
90.Paladini, D, Sglavo, G, Pastore, G, Masucci, A, D’Armiento, MR, Nappi, C. Aberrant right subclavian artery: incidence and correlation with other markers of Down syndrome in second-trimester fetuses. Ultrasound Obstet Gynecol 2012; 39: 191–5.CrossRefGoogle ScholarPubMed
91.Zalel, Y, Achiron, R, Yagel, S, Kivilevitch, Z. Fetal aberrant right subclavian artery in normal and Down syndrome fetuses. Ultrasound Obstet Gynecol 2008; 31: 25–9.Google Scholar
92.Benacerraf, BR. The history of the second-trimester sonographic markers for detecting fetal Down syndrome, and their current role in obstetric practice. Prenat Diagn 2010; 30: 644–52.Google Scholar
93.Daley, R, Hill, M, Chitty, LS. Non-invasive prenatal diagnosis: progress and potential. Arch Dis Child Fetal Neonatal Ed. 2014. doi: 10.1136/archdischild-2013-304828. [Epub ahead of print].Google Scholar
94.Lewis, C, Hill, M, Chitty, LS. Non-invasive prenatal diagnosis for single gene disorders: experience of patients. Clin Genet 2014; 85: 336–42.Google Scholar
95.Bethune, M. Literature review and suggested protocol for managing ultrasound soft markers for Down syndrome: thickened nuchal fold, echogenic bowel, shortened femur, shortened humerus, pyelectasis and absent or hypoplastic nasal bone. Australas Radiol 2007; 51: 218–25.Google Scholar
96.Kirwan, D and NHS Fetal Anomaly Screening Programme (NHS FASP). The 18+0 to 20+6 Weeks Fetal Anomaly Scan - National Standards and Guidance for England. UK National Screening Committee, University of Exeter, January 2010. http://fetalanomaly.screening.nhs.uk/getdata.php?id=11218. Accessed on 7 December 2014.Google Scholar
97.Chitayat, D, Langlois, S, Wilson, RD, Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada, Prenatal Diagnosis Committee of the Canadian College of Medical Geneticists. Prenatal screening for fetal aneuploidy in singleton pregnancies. J Obstet Gynaecol Can 2011; 33: 736–50.CrossRefGoogle ScholarPubMed