Aneuploidy
The goal is to always rule out
aneuploidy.
For Down's syndrome, there is a simple sonographic scoring index graded by Benacerraf:
2pts Major anomaly
2pts Nuchal fold thickening (50% sensitive)
1pts Short femur (47% sensitive)
1pt Short humerus (41% sensitive)
1pt Pyelectasis (22% sensitive)
1pt Hyperechoic bowel (25% sensitive)
1pt Echogenic cardiac focus (equal to or greater than bone) (30% sensitive)
NB nasal bone U/S is considered to be very good for Down's detection, but is in its infancy
Maternal age factors:
0pt <35
1pt 35-40
2pt >40yrs
Scoring:
>=2 pts 76% Down's detection with 5.7% false positive
>=1 pt 83% Down's detection with 18% false positive
text
Tools
For Down's syndrome, there is a simple sonographic scoring index graded by Benacerraf:
2pts Major anomaly
2pts Nuchal fold thickening (50% sensitive)
1pts Short femur (47% sensitive)
1pt Short humerus (41% sensitive)
1pt Pyelectasis (22% sensitive)
1pt Hyperechoic bowel (25% sensitive)
1pt Echogenic cardiac focus (equal to or greater than bone) (30% sensitive)
NB nasal bone U/S is considered to be very good for Down's detection, but is in its infancy
Maternal age factors:
0pt <35
1pt 35-40
2pt >40yrs
Scoring:
>=2 pts 76% Down's detection with 5.7% false positive
>=1 pt 83% Down's detection with 18% false positive
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Tools
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