3. NON - INVASIVE TOOL
PROVIDES A TANGIBLE & REALISTIC
MODALITY
PATIENTS CAN VISIBLY SEE FOR
THEMSELVES
COST EFFECTIVE
HIGH SENSITIVITY IN DETECTING
MARKERS/ANOMALIES
MORE SOPHISTICATED & HIGH-
RESOLUTION USG

4. OBSERVATION CHROMOSOMAL
ABNORMALITY
HEAD TRISOMY-18,13
•Strawberry skull TRIPLOIDY
•Hydrocephalus
•Holoprosencephaly
•Choroid plexus cyst
FACE TRISOMY-13,18
•Cleft lip/cleft palate Meckel-Gruber syndrome
•Low set ears TRIPLOIDY
HEART TRISOMY-13,18,21
•VSD,ASD
•Coarctation of aorta

5. OBSERVATION CHROMOSOMAL
ABNORMALITY
RENAL TRISOMY-13,18,21
• Horseshoe kidney TRIPLOIDY
• B/L dilatation of renal pelvis
• Cystic dysplasia
HANDS/FEET TRISOMY-18,13,21
•Flexed overlapping fingers
•Rocker bottom/club foot
•Polydactyly
•Wide gap b/w 1st &2nd toes
(Sandal-gap)
•Clinodactyly
•Short femur/humerus

6. OBSERVATION CHROMOSOMAL
ABNORMALITY
G.I SYSTEM TRISOMY-13,18
Omphalocele TRISOMY-21
Duodenal atresia
Echogenic bowel
GENERAL
Growth restriction TRISOMY-13,18,21
Hydrops TRIPLOIDY;45-XO

7. OBSERVATION CHROMOSOMAL
ABNORMALITY
PLACENTA Partial mole
ANEUPLOIDY
UMBILICAL CORD TRISOMY-18

8. NUCHAL TRANSLUCENCY
With severe
LYPHANGIECTASIA
→ overall swelling
of the fetal soft
tissue
↓
Thickening of the
nuchal soft tissues
↓
NUCHAL
TRANSLUCENCY

9. Refers to the normal
subcutaneous fluid filled space
between the back of the fetal neck
& the overlying skin.
The single most powerful marker
available today for differentiating
DS from euploid pregnancies.

11. POSSIBLE CAUSES OF ↑ FLUID FILLED SPACE(NT)
Cardic failure secondary to structural
malformation
Abnormality in the extracellular matrix
Abnormal or delayed development of
the lymphatic system

12. CAUSES
ANEUPLOIDIES SKELETAL DYSPLASIA
Carnelia de Lange Achondrogenesis
Noonan syndrome Ectrodactyly-ectodermal
Smith-Lemli-Opitz dysplasia
Joubert Multiple Pterygium Syndrome
Apert Robert Syndrome
Fryns
CHROMOSOMAL ANOMALIES
Trisomy-21 (most common)
Trisomy-13,18,22
Triploidy
Tetrasomy -12p

13. Imaged in the mid sagittal plane, ideally with the fetal
spine down.
Image should be adequately magnified so that only
the fetal head ,neck & upper thorax fill the viewable
area
The fetal neck should be neutral-avoid measurements
in the hyperflexed/hyper extended positions
The skin at the fetal back should be clearly
differentiated from the underlying amniotic membrane

14. Measurement calipers
should be optimized to
ensure clarity of the image
and of the borders of the
nuchal space in particular
(TVS)
The width of the lucency
alone, excluding the width
of the surface or occiput

16. PITFALLS
PRESENCE OF
 An Encephalocele
 Nuchal cord
 An Amniotic band
 A loose amnion that can be
mistaken for the nuchal skin edge

17. How to rectify?
MAGNIFY THE IMAGE
WAIT FOR SPONTANEOUS FETAL ACTIVITY
→ as the fetus bounces from the amnion ,the
edges can be distinguished more reliably
COLOR DOPPLER → presence of a umbilical
cord in the vicinity of the fetal neck.

18. Cut off value of 3mm as a threshold for an
abnormal nuchal translucency
Normal NT thickens with increasing GA
Currently, the more accepted method is to
base the cut off on a progressive rise
>95th percentile as a threshold.
MOM Vs SD: MOM-reduction in false +ve rates

19. •Equal success (Braithwaite & Economides)
METHOD Gestational Age Success rate
TAS 10-13 WEEKS 98% to 100%
TAS AT 14 WEEKS 90%
TVS is needed

20. 10-14weeks of GA
Detection rate False+ve rate Study group
77% 5% Fetal medicine
foundation,
London
63% 5% The SURUSS
trial,UK
69% 5% The BUN trial,
US
70%-64% 5% The FASTER
trial, US

21. Nicholaides: First trimester NT =/> 3mm
Detection rate→86% of Trisomic fetus
False +ve rate→4.5%
Pandya (1995):
NT (mm) 3 4 5 >6
RISK ↑ 3 18 28 36
•TRISOMIES 13,18,21
•FETAL LOSS RATE =15% with NT of 5mm
•↑ NT → ↑ RISK OF CONGENITAL HEART DEFECT
•With Normal Karyotype & with abnormal karyotype

22. Progression from an abnormal NT to a
normal one→ not necessarily indicative of a
nomal Karyotype
So the fetus with nuchal abnormalities →
candidates for amniocentesis ,regardless of
whether the abnormality resolves
Among the women with advanced maternal
age b/w 11-14wks GA→NT can be used to
determine which patients would benefit from
an early First trimester Amniocentesis/CVS,
Vs delay of the invasive testing until 16 weeks
for the safest possible procedure.

23. MAJOR CARDIAC ANOMALIES
DIAPHRAGMATIC HERNIA
ANT. ABD.WALL DEFECT
FETAL AKINESIA/DYSKINESIA SYNDROME
OTHERS- Cornelia de lange,Noonan,Smith-lemli-
Opitz,Joubert,Apert&Fryns
SKELETALANOMALIES→
Achondrogenesis,Ectrodactyly-ectodermal
dysplasia,Multiple Pterygium syndrome,Robert syndrome

24. Localised nuchal fluid→CYSTIC HYGROMA(CH)
FETAL HYDROPS
DIFFUSE EDEMA
SEPTATED CH:
ANEUPLOIDY EUPLOID
50% 50%
50%-MAJOR structural
malformation
CARDIAC x12
SKELETAL DYSPLASIA

26. Presence of Septations within
a nuchal swelling is ominous
Non - Septate CH Septate CH
98%- transient 44%-transient
6%→ Abnormal 72%→ Abnormal
Karyotype Karyotype
Bronshtein et al.

27. NO NEED TO DELAY DECISION MAKING→
while awaiting serum marker results/using
computerized risk calculation algorithms
IMMEDIATE OPTIONS FOR CVS
IF NO FETAL ANEUPLOIDY→
A DETAILED FETAL ANATOMIC
EVALUATION
+ FETAL ECHOCARDIOGRAPHY AT 18-20
WEEKS

28. FASTER TRIAL-
>3mm NT → CVS SHOULD BE OFFERED
IMMEDIATELY,because of a minimum risk of
aneuploidy of 1 in 6.
NO ROLE FOR DELAYING DECISION
MAKING while awaiting serum marker
results,because such additional information
does not meaningfully alter the original
aneuploidy risk

29. GROWTH PATTERNS- CRL
NASAL BONE
DUCTUS VENOSUS SONOGRAPHY
TRICUSPID REGURGITATION
ANTERIOR ABDOMINAL WALL DEFECTS
ENCEPHALOCELES
LIMB DEFORMITIES
HEART DEFECTS

30. Schemmer et al;
CRL→ NOT significantly reduced
with Trisomy-21,Turner Syndrome or
Sex chromosome Trisomies
 → SIGNIFICANTLY reduced
growth rates with Trisomies 13 & 18
and Triploidy

31. ABSENCE OF NASAL BONE & DS
Cicero et al; (N= 701 fetuses with ↑NT)
ABSENCE OF NB PRESENCE OF NB
73% 0.5%
(43 OF 59) (3 OF 602)
NOT RELATED TO ↑ NT
COULD BE COMBINED INTO A SINGLE USG
SCREENING MODALITIES
PREDICTED SENSITIVITY OF 85% FOR 1% FALSE +VE
RATE.

32.  MID SAGITTAL PLANE
 FETAL PROFILE FACING
UPWARD
 ADEQUATE MAGNIFICATION
 VISUALIZATION OF TWO
PARALLEL LINES AT THE
LEVEL OF THE FETAL NOSE→
1. Superficial: fetal skin
2. Deeper: nasal bone
 NASAL BONE- MORE
ECHOLUCENT AT THE DISTAL
END.

33. INCIDENCE OF ABSENT NASAL BONE
GENERAL HIGH RISK
POPULATION POPULATION
17%-29% 48%
LIMITED ROLE AS A SCREENING TOOL FOR
GENERAL POPULATION

34. FORWARD TRIPHASIC
PULSATILE FLOW→
NORMAL
REVERSED FLOW AT THE
TIME OF ATRIAL
CONTRACTION
→ANEUPLOIDY/FETAL
CARDIAC MALFORMATION
WITH NT → ↑ THE DETECTION RATE/↓ THE FALSE +VE
RATE

35. PITFALLS
The ductus venosus vessel- as small as
2mm at 10-14weeks
Very difficult to get proper image
SECONDARY SCREENING TEST IN
THE HANDS OF EXPERIENCED
SONOLOGIST

36. CHEST WALL-ANTERIOR
THE FETAL HEART SHOULD
BE ISONATED PARALLEL TO
THE VENTRICULAR SEPTUM
HIGH RISK PREGNANCIES
AT 11-13 WEEKS
Significant TR INCIDENCE
NORMAL FETUS 4%
DS Fetus 68%
TRISOMY- 18 33%
SECOND LINE TEST

37. AT 10-14 WEEKS
Normal parameters
GA(weeks) FHR (beats/min)
10 171
14 156
Higher than normal rate- TRISOMY-21
Lower than normal rates- TRIPLOIDY & TRISOMY-18

38. SENSITIVITY
ABNORHAL FHR- 26%
NT- 72%
MATERNAL AGE- 48%
MATERNAL AGE+ NT + FHR- 83% of
detection rate at 5% false +ve rate

39. Authors Parameter Sensitivity False +ve rate
Orlandi et al. NT alone 57% 5.8%
NT + 87% 5.8%
biochemistry &
maternal age
Noble et al; NT + 80-85%
Biochemistry &
maternal age
BEST DETECTION RATE IN 1ST TRIMESTER-
Urine free β- hCG , beta core & Oestriol + NT

40. 10-14 WEEKS
NT SONOGRAPHY
CYSTIC HYGROMA NO CYSTIC HYGROMA
CVS
SINGLETONE MULTIFETAL
EUPLOID ANEUPLOID GESTATION GESTATION
18-20 WKS COUNCEL
ANATOMY
SCAN &
FETAL ECHO

41. NT + NO CYSTIC HYGROMA
SINGLETONE GESTATION MULTIFETAL GESTATION
NT + SERUM MARKERS NT INTERPRETED WITH
PAPP-A & β- hCG MATERNAL AGE ONLY
RISK ↑ RISK ↑
RISK NOT↑
CVS EUPLOID CVS
EUPLOID
ANEUPLOID ANEUPLOID
18-20 WKS
COUNCEL ANATOMY SCAN & COUNCEL
FETAL ECHO

42. MOST COMMON SONOGRAPHIC MARKERS
NUCHAL FOLD THICKENING
ECHOGENIC INTRACARDIAC FOCUS
SHORTENED LONG BONES
HYPERECHOIC BOWEL
RENAL PYELECTASIS
CHOROID PLEXUS CYST
CLINODACTYLY
HYPOPLASTIC OR ABSENT NASAL BONE

43. EXCESS SOFT TISSUE IN THE POSTERIOR NECK AREA
Measurement
TS OF FETAL HEAD
ANGLED POSTERIORLY
TO INCLUDE THE
CEREBELLUM & THE OCCIPITAL N T
BONE
OUTSIDE OF THE OCCIPITAL BONE
OUTER SKIN EDGE

44. THE NUCHAL SKIN FOLD MEASUREMENT THRESHOLD
AUTHORS Gestational Threshold
Age
Gray & Crane 14-17 wks 5mm
18-20 wks 6mm
Wilson < 17wks 5mm

45. SENSITIVITY
AUTHORS CUT OFF VALUE SENSITIVITY FALSE +VE
Crane & >/= 5 mm 75%
Gray
Borrell & >/= 6 mm 33% 0.1%
Colleagues
Borrell & >/= 5mm 77.8% 2%
Colleagues

46. May persists throughout the 2nd trimester
Or regression may occur

47. ONCE AN ABNORMAL NUCHAL SKIN
MEASUREMENT IS OBTAINED,THEREFORE ,AN
AMNIOCENTESIS IS INDICATED, REGARDLESS
OF WHETHER THE NUCHAL SKIN THICKNESS
RESOLVES

48. TRISOMY-21 oSHORT STATURED
oSHORT FEMURS
oSHORT HUMERI
RATIOS OF THE MEASURED - TO - EXPECTED FL OF
</= 0.91, BPD.
EXPECTED FL = - 9.3105 + 0.9028 x BPD

49. SENSITIVITY
STUDY SENSITIVITY FALSE +VE RATE
LOCKWOOD 50% 7%
CALLEN 68%
GRIST 50% 6.5%

50. Study Parameter Sensitivity False +ve Anomalies
rate
Brumfield BPD: FL 40% 2.2% TRISOMY-
et al; >/= 1.8 18 & 21
Ginsberg -do- 53% 7% - do-
et al;
Ginsberg + NT 81% 7% - do-
et al;
NOT A HELPFUL TOOL FOR SCREENING OF DS
USEFUL IN COMBINATIONS WITH OTHER SONOGRAPHIC MARKER
Eg: HUMERUS LENGTH & PYELECTASIS

51. THE MEASURED- TO – EXPECTED HUMERUS LENGTH
= - 7.9404 + 0.8492 x BPD
< 0.90 as a cut - off
STUDY METHODS SENSITIVITY FALSE +VE
Callen HL 50% 6.25%
Rodis et al; HL 54%
FL 18%
Biagiotti FL + HL ↑ ↓↓
Periti
Cariati

52. Nyberg et al; Short FL + HL 11 fold ↑ risk of
DS
Johnsons et al; FL+ HL 53% - sensitivity
Foot Length 7% - false +ve
rate

54. An antero-posterior diameter of the renal pelvis
>/=4 mm

55. STUDY METHOD SENSITIVITY FALSE +VE
Callen PYELECTAS 25%
IS
Crane & -do- 18.7%
Gray
Corteville , -do- 17% 2%
Dicks &
Crane
ISOLATED PYELECTASIS- ↑risk
NOT SUFFICIENT TO INDICATE AMNIOCENTESIS
USED IN COMBINATION WITH OTHER

56. THE BOWEL IS AS ECHOGENIC AS BONE
0.6% OF ALL 2ND -
TRIMESTER FETUSES
BE AWARE:
High frequency transducer
may tend to accentuate the
echogenicity of the fetal
bowel in NORMAL fetus

57. ↑ RISK OF
IUGR
PREMATURITY
FETAL DEMISE
POOR PERINAL OUTCOME
APH
 CYSTIC FIBROSIS - Parental allele testing for CF
carrier status is recommended
 IN-UTERO CMV INFECTION

58. MINERALIZATION IN THE PAPILLARY MUSCLE
UNILATERAL BILATERAL

59. 90% in the left ventricles
When the Right ventricle or both ventricles
are involved ↑ risk of Chromosomal anomalies
FETAL STATUS EIF in Left EIF in Right / B/L
Ventricle
Normal 88% 12%
Down Syndrome 78% 22%

60. STUDY NORMAL TRISOMY- 21 TRISOMY- 13
Brown,Roberts 2% 16% 39%
& Miller
Callen 4.7% 18%
Association of EIF & Chromosomal anomalies is low
in low risk patient
NO AMNIOCENTESIS
Not associated with cardiac anomalies in low risk
patient

61.  NORMAL FETUSES - 0.3% TO 3.6%
 1/3RD OF FETUSES WITH TRISOMY - 18
•16-21 WEEKS → TRANSIENT
•BY 23RD WEEKS → USUALLY REGRESS
•25-26 WEEKS → UNCOMMON

62. U/L SINGLE SMALL
B/L MULTIPLE LARGE
SIZE = 0.5 cm – 2cm
Very large CPC → Fill almost the entire
lateral ventricle & expands its walls →
FALSE VENTRICULOMEGALY

63. + OTHER ISOLATED CPC
SONOGRAPHIC
FINDINGS
CONSERVATIVE
INVASIVE TESTING With detailed fetal
sonographic anatomic
survey by experts

64. EXAMINING THE UA TRANSVERSE VIEW OF A FREE
RUNNING ALONGSIDE & LOOP OF CORD
AROUND THE BLADDER
Transverse view of the pelvis

65. 17% - CYTOGENETIC ABNORMALITY
TRISOMY- 18 ( Most Common )
TRISOMY- 13
TURNERS SYNDROME (45X)
TRIPLOIDY
Commonly seen in normal fetuses
It is non-specific
The most common organ system
involved – HEART , GI SYSTEM & CNS

66. A targeted & detailed fetal ISOLATED SUA –
anatomic survey should be No ↑ incidence for a
done with detailed chromosome
evaluation of the heart abnormality

67. ILIAC WING ANGLE
ILIAC LENGTH
FRONTOTHALAMIC DISTANCE (BRACHYCEPHALY)
SHORTENED FRONTAL LOBE
ABNORMAL FHR
ABNORMALLY SHORTENED EAR LENGTH
FLAT FACIES
CLINODACTYLY(with hypoplasia of the middle
phalanx of the fifth digit)
SANDAL GAP GREAT TOE
SIMIAN CREASE OF THE PALM
EAR LENGTH & WIDTH

68. LOW RISK NO further Testing
Normal USG
No markers present
HIGH RISK DS risk adjustment
LOW RISK NO further Testing
1-ISOLATED MARKER
(Except-Nuchal fold/
Absent Nasal Bone Genetic Amniocentesis
HIGH RISK
>/=2 MARKERS/Thick LOW RISK Genetic Amniocentesis
Nuchal Fold/ Absent
Nasal Bone/Structural
Anomaly HIGH RISK Genetic Amniocentesis

69. STRUCTURAL ABNORMALITIES ANEUPLOIDY MARKERS
oCardiac defects Clinodactyly
oCystic hygroma EIF
oVentriculomegaly/hydrocephalus Hyperechoic bowel
oEsophageal atresia Nuchal fold thickening
/Tracheo-esophagial fistula Pyelectasis
oDuodenal atresia Sandal gap
oOmphalocele Short long bones
Wide iliac angle
OTHER FINDINGS
SUA
Brachycephaly
Short ear length
Flat facial profile
Absent / hypoplastic
Protruding tongue
nasal bone
Hydrops
Hydrothorax
Pericardial effusion
Unfused amnion & chorion after 14 weeks

70. STRUCTURAL ABNORMALITY
Cardiac defect
Cystic hygroma
Diaphragmatic hernia
Omphalocele
Esophageal atresia+/- TOF
CNS-agenesis of
corpuscallosum,ventriculomegaly,hydrocephalus,large
cisterna magna,Dandy-Walker Malformation,cerebellar
dysgenesis,neural tube defect
CRANIOFACIAL- Strawberry-shaped skull,prominent
occiput,dolichocephaly,ocular anomalies,micrognathia,cleft
lip/palata,small,low set ears
GENITO-URINARY- Hydronephrosis,horseshoe
kidney,BOO,duplication abnormality,genital abnormality

71. EXTREMITY-
Limb reduction abnormality,Radial
aplasia,Clenched hands/Overlapping
digits,Club feet,Rocker-bottom feet,Lower
extremity/feet
abnormality,Contracture/arthrogryposis/flexion
deformity,movement disorders
ANEUPLOIDY MARKERS- OTHER FINDINGS-
 Choroid plexus cyst IUGR,Amniotic fluid
Strawberry-shaped skull abnormality,Umbilical
Nuchal thickening cord cyst,Non immune
hydrops
Single Umbilical artery
Shortened limbs

72. STRUCTURAL ABNORMALITIES-
Cardiac defects,Cystic hygroma,Nuchal
thickening,Omphalocele
CNS- Holoprosencephaly,Agenesis of corpus callosum,
Ventriculomegaly,Enlarged cisterna magna,Abnormal posterior
fossa,Neural tube defects
CRANIO-FACIAL- Microcephaly,Micrognathia,Cleft
lip/palate,Facial defects,Ocular anomalies ,Sloping
forehead,Small ears
EXTREMITIES- Postaxial polydactyly,Overlapping
digits,Camptodactyly,Radial aplasia,Rocker-bottom feet,Club feet
UROGENITAL- Hydronephrosis,Cortical cysts,Horseshoe
kidney,Echogenic kidney,Polycystic kidneys

73. ANEUPLOIDY MARKERS
Echogenic Intracardiac Focus
Pyelectasis
Single Umbilical Artery
OTHER FINDINGS
Microcephaly
IUGR
Polyhydramnios

99. PAST
Over the past decade & a half, AMNIOCENTESIS was reserved
for woman of advanced maternal age
PRESENT
In the new millenium- major changes in the indications for
INVASIVE GENETIC TESTING- such that advance maternal
age alone will no longer be an indication
FUTURE
Whether a patient is at risk for fetal Aneuploidy will be based on
the combination MATERNAL AGE,MULTIPLE BIOCHEMICAL
SERUM MARKERS & perhaps a dozen SONOGRAPHIC MARKERS
+ a complete USG evaluation of the fetus.