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Online ISSN
1305-3124

Established
1993

Editors-in-Chief
​Cihat Şen, ​Nicola Volpe

Editors
Cecilia Villalain, Daniel Rolnik, M. Mar Gil

Managing Editors
Murat Yayla

Statistics Editor
Resul Arısoy

Ultrasonographic findings in pregnants with Down syndrome

Cüneyt Eftal Taner, Mustafa Oğuz Aygören, İlkan Kayar, Gülsen Derin

Article info

Ultrasonographic findings in pregnants with Down syndrome. Perinatal Journal 2009;17(2):65-69

Author(s) Information

Cüneyt Eftal Taner,
Mustafa Oğuz Aygören,
İlkan Kayar,
Gülsen Derin

  1. Ege Doğumevi ve Kadın Hastalıkları Eğitim ve Araştırma Hastanesi, Kadın Hastalıkları ve Doğum Kliniği- İzmir TR
Publication History
Conflicts of Interest

No conflicts declared.

Objective
Review the ultrasonographic features of down syndrome cases during pregnancy.
Methods
Ultrasonographic features of Down syndrome cases diagnosed with karyotype investigations due to advanced maternal age, increased risk in biochemistry tests, and structural anomalies diagnosed during ultrasonography.
Results
Ultrasonographic features of 19 cases with Down syndrome were reviewed in a group of 1204 karyotipe investigation. In 7 cases ultrasonographic features were normal (36.8%). In 7 cases nuchal folds were increased. In 4 cases (21.1%) pelvicaliectasis were detected. In 2 other cases there were omphalocel and cardiac anomalies, and cystic hygroma and cardiac echogenic focus was detected in one cases.
Conclusion
During ultrasonographic investigations structural anomalies and soft markers should carefully searched and than decision for invasive procedures were should be considered.
Keywords

Down syndrome, ultrasonography, prenatal diagnosis

Introduction
During ultrasonographic investigations some detected soft markers are related with Down syndrome and other aneuploidies such as increased nuchal fold thickness, echogenic bowels, short femur length, pyelectasis, hypoplastic nasal bone, choroid plexus cyst, echogenic intracardiac focus (1). Prenatal biochemical tests are more valid than second trimester ultrasonographic investigations for diagnosis of Down Syndrome. Structural anomalies are friquently related with chromosomal anomalies. Soft markers increases amniocentesis and this may lead to a little increase in abortion rates. In this study, ultrasonographic soft markers of fetuses diagnosed of Down Syndrome are retrospectively reviewed.
Methods
Our study group consisted of 19 cases with Down Syndrome . Amniocentesis was indicated in 1204 women due to family history of aneuploidies, maternal age, increased risk in biochemical tests, ultrasonographic soft markers and structural anomalies in these fetuses during the years 2006 and 2007. Ultrasonographic findings of these cases detected during ultrasonographic investigations which were performed in 11-22 weeks gestations were reviewed. The fetuses without karyotype analysis or diagnosed postnatally were not taken in to the study group since their records can not be reached. Early fetal deaths were also not included. Ultrasonographic investigations were made by using a Medison 3.5 MHz probe by our hospital physicians. Amniocentesis were performed by our physians under ultrasonography by using 22 g spinal needles after two times of povidone iodine aplication to lower abdomen. Our soft markers are nuchal translucensy more than 3 mm, nuchal fold thickness more than 6 mm (1,2), choroid plexus cysts independent of number and size, intracardiac echogenic focus, echogenic bowels, renal pyelectasis (when anteroposterior length of renal pelvis is more then 4 mm), short femur or humerus length when actual length is shorter than 85 % of expected length. Since ultrasonografic investigations were made by different physicians, we couldn’t reach nasal bone findings in all hospital recordings. For this reason nasal bone findings are not included in our evaluation. All structural anomalies and soft markers were recorded.
Results
Ultrasonographic findings of 19 cases with Down syndrome diagnosed with karyotype investigations were included as the study group. Between 2006-2007 years we find out 1204 karyotypic analysis performed for advanced maternal age, increased risk in biochemical tests, structural anomalies and soft markers detected during ultrasonography and history of chromosomal anomalies in the family., Nineteen of cases were diagnosed as trisomy 21. Six patients were older than 35 years in this group. Mean maternal age of 19 cases was 30.9, average parity was 1.1, and mean gestational age was 18 weeks at the time of amniocentesis. Ultrasonographic findings of 19 cases with Down Syndrome are listed Table I : In 9 cases there were more than one ultrasonographic finding. All cases with Down Syndrome were discussed at our perinatology council. After situation was explained to the parents 16 cases were inducted by misoprostol. Three patients refused the council decision, 2 of those had gone cesarean section due to ablatio plasenta and fetal distress, one case was born spontaneously.
Discussion
Down Syndrome is seen in 1.41 of 1000 live births and ıt’s the one of the most important chromosomal anomalies that is investigated by perinatologists (3). Ultrasonographic soft markers are, increased nuchal fold thickness, echogenic bowels, short femur-humerus length, pyelectasis, echogenic intracardiac focus, and choroid plexus cyst. Nasal bone aplasia and hypoplasia were added to the list afterwards. All these markers are useful clues for diagnosis of Down Syndrome (4). Cardiac anomalies are seen at about 50 % of Down Syndrome patients (5). In spite of different study results structural anomalies can be detected at about 30 % of Down Syndrome cases by second trimester ultrasonographic investigations (6-8). Yıldırım reported that 12.9 % of the cases had chromosomal anomalies and 4.6 % of these cases had Down syndrome in a group of cases with fetal anomalies detected during ultrasonography. They concluded that detection of chromosomal anomalies by amniocentesis was higher in cases with fetal anomalies rather than advanced maternal age or risk in triple test.(9) Sener reported that they foud pathologic ultrasonographic features in 30 % of cases with Down syndrome (10). Soft markers are usually found with structural anomalies (11). Furthermore it’s said that isolated soft markers such as choroid plexus cyst, echogenic bowel, short femur, short humerus are not related with Down Syndrome. In our series there was no ultrasonographic marker among 7 cases. If it would be possible; could be find any marker in these pregnants?. The main question is what shall we do when find a soft marker. These markers can be found at about 14-15 % of normal second trimester pregnancies. False positivity and fetal deaths due to invasive diagnostic procedures will increase if we prefer karyotype analysis for every soft marker detected. According to Bindman et al. İsolated soft markers are seen at 13.9 % of Down Syndrome cases and 9.3 % of normal fetuses (11). The most common anomalies are congenital cardiac defects, cerebral ventriculomegalies, cystic hygroma, hydrops, hydrotorax, omphalocel, duodenal atresia and abnormal extremities (8,12). Boyd et al reported that soft markers, increased the detection of malformation diagnosis rate by 4 % but on the other hand false positivity increased by 12 times (13). Because of these increased likelihood ratio was proposed to be 2.0 when evaluating the soft markers (14). And in the abcense of soft markers the case should be removed from the high risk group (15). Nasal bone aplasia was detected in 0.5 % of normal fetuses and 43 % of trisomy 21 cases at Bromley’s study (16) and they concluded that this soft marker increased the likelihood ratio 83 times. In our study we detected one nasal bone aplasia and one nasal bone hypoplasia (10.52 %). This low percentage in our study may be due to evaluations done by different physicians. Also those patients may not be evaluated with same interest and care. In our opinion this ratio will increase when evaluations were done by well educated and carefull physicians. Bromley and et al reported that nuchal fold thickness 6 mm and/or more at 15-22 weeks of gestation increases trisomy 21 risk by 17 times but noted that this is not a common finding (13,17). In our study, in 5 cases nuchal translucency and in 2 cases nuchal fold thickness was increased. Isolated increased nuchal fold thickness was seen at 4 % of Down Syndrome cases and together with 26 % of other anomalies (17). It’s accepted that this soft marker, even in isolated form, increases Down Syndrome risk (17-18). Hyperechogenic bowel is encountered at 15 % of trisomy 21 patients and 6.6 % of normal fetuses (19). We have no case with this finding in our study group. It should not be forgotten that hyperechogenic bowel can be related with swallowed blood, cystic fibrosis disease and fetal infections. It’s known that short femur and humerus length increases chromosomal anomaly risk (20-21). 2.5 times increase at standard percentiles is accepted as diagnotic criteria (22) and short humerus length is more diagnostic than femur length (16,23). So it’s advised to measure humerus length during second trimester ultrasonographic investigation (14). Choroid plexus cysts are encountered in 25-30 % of cases with trisomi 18 and 1 % of normal fetuses. They vary 3-16 mm in size can be detected at 14-16 gestational weeks and disappear at 22. gestational week. They are not accepted as soft markers for trisomy 21 but their importance is; they direct to reexamine fetal structures that may be related with trisomy 18. Renal pyelectasis is seen at 17 % of Down Syndrome cases. We detected this finding in 4 of our 19 patients (21 %). Aneuploidy ratio is 1/300 at isolated pyelectasis and this situation may also be related with hydronephrosis or postnatal urinary reflu disease (24-25). Isolated pyelectasis is not accepted as an increased risk factor for trisomy 21 risk (7). Middle phalanx hypoplasia of 5th finger, sandal gap, fetal ear size, brachycephaly are the other ultrasonographic findings, but these usually take place in case reports and not accepted as soft markers (14). Single umblical artery may also seen in aneuploidic fetuses but it is usually together with other findings (24-26). Isolated single umblical artery is not related with increased aneuploidy risk (14).
Conclusion
As a conclusion when a soft marker is detected its risk accelaration should be considered than decision for invasive procedures should be evaluated Fetal structures should be reinvestigated carefully and than invasive procedures should be considered.
References
1. Twining P. Chromosome abnormalities. In: Twining P, Mc Hugo JM, Pilling DW (Eds). Textbook of Fetal Abnormalities. Philadelphia: Churchill Livingstone: 2000; p: 315-44:
2. Shipp TD, Benacerraf BR. Second trimester ultrasound screening for chromosomal Abnormalities. Prenat Diagn 2002; 22: 296–307.
3. Wright DE, Bray I. Estimating birth prevalence of Down’s syndrome. J Epidemiol Biostat 2000; 5: 89-97.
4. Kafkaslı A. Gebelikte Down Sendromu Tanısı için Tarama Testleri ve Güvenilirlikleri. TJD Uzmanlık Sonrası Eğitim Dergisi 2004; 6: 30-5.
5. DeVore GR. The role of fetal echocardiography in genetic sonography. Semin Perinatol 2003; 27: 160-72.
6. Rotmensch S, Liberati M, Bronshtein M et al. Prenatal sonographic findings in 187 fetuses with Down syndrome. Prenat Diagn 1997; 17: 1001-19.
7. Vintzileos AM, Egan JFX. Adjusting the risk for trisomy 21 on the basis of second trimester ultrasonography. Am J Obstet Gynecol 1995; 172: 837-44.
8. Nyberg DA, Resta RG, Luthy DA, Hickok DE, Mahony BS, Hirsch JH. Prenatal sonographic findings of Down syndrome review of 94 cases. Obstet Gynecol 1990; 76: 370-77.
9. Yıldırım G ve ark. İkinci trimester genetik amniyosentez sonrası gebelik sonuçları: 1070 olgunun değerlendirmesi. Perinatoloji Dergisi 2006; 14: 129-34.
10. Şener KT, Durak B, Tanır HM ve ark. Kliniğimizde 7 yıllık amniosentez sonuçları. Perinatoloji Dergisi 2006; 14: 170-5.
11. Bindman RS, Chu P, Goldberg JD. Second trimester prenatal ultrasound for the detection of pregnancies at increased risk of Down syndrome. Prenatal Diagn 2007; 27: 535-44.
12. Banacerraf BR. Should sonographic screening for fetal Down syndrome be applied to low risk women? Ultrasound Obstet Gynecol 2000; 15: 451-5.
13. Boyd PA, Chamberlain P, Hicks NR. Six year experience of prenatal diagnosis in an unselected population in oxford, UK. Lancet 1998; 352: 1577-81.
14. 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. Australian Radiology 2007; 51: 218-25.
15. Nicaloides KH. Screening for chromosomal defects. Ultrasound Obstet Gynecol 2003; 21: 313-21.
16. Bromley B, Lieberman E, Shipp TD, Benacerraf BR. Fetal nose bone lenght: a marker for Down syndrome in the second trimester. J Ultrasound Med 2002; 12: 1387-99.
17. Bindman RS, Hosmer W, Feldstein VA, Deeks JJ, Goldberg JD. Second trimester ultrasound to detect fetuses with Down syndrome. JAMA 2001; 285: 1044-55.
18. Guyatt G, Rennie D. Evidence Based Medicine Working Group American Medical Association 2002. Users guide to the medical literature. A manuel for evidence based clinical practice. AMA Press; Chicago, IL: AMA Press; 2002.
19. Bromley B, Doubilet P, Frigoletta FD jr, Krauss C, Estroff JA, Benacerraf BR. Is fetal hyperechogenic bowel on second trimester sonogram an indication for amniocentesis? Obstet Gynecol 1994; 83: 647-51.
20. Fitz Simmons J, Droste S, Shepard TH, Pascoe-mason J, Chinn A, Mack LA. Long bone growth in fetuses with Down syndrome. Am J Obstet Gynecol 1989; 161: 1174-7.
21. Lockwood C, Benacerrat B, Krinsky A, et al. Sonographic screening method for Down syndrome. Am J Obstet Gynecol 1987; 157: 803-8.
22. Van der Hof MC, Wilson RD. Diagnostic Imaging Committee. Society of Obstetricians and Gynaecologists of Canada; Genetic Committee, Society of Obstetricians and Gynaecologists of Canada. Fetal soft markers in obstetric ultrasound. J Obstet Gynecol Can 2005; 27: 592-636.
23. Nyberg DA, Souter VL, El Bastawissi A, Young S, Luthhard F, Luthy DA. Isolated sonographic markers of detection of fetal Down syndrome in the second trimester of pregnancy. J Ultrasound Med 2001; 20: 1053-63.
24. Coco C, Seanty P.Isolated fetal pyelectasis and chromosomal abnormalities. Am J Obstet Gynecol 2005; 193: 732-8.
25. Cortville JE, Bicke JM, Crane JP. Fetal pyelectasis in Down syndrome: is genetic amniocentesis warranted? Obstet Gynecol 1992; 79: 770-72.
26. Chudleigh PM, Chitty LS, Pembrey M, Campbell S. The association of aneuploidy and mild fetal pyelectasis in unselected population: the results of a multicenter study. Ultrasound Obstet Gynecol 2001; 17: 197-202.a
File/Dsecription
Table 1.
Ultrasound findings in Down syndrome cases.