###Rationale: (D) Nuchal edemaINCIDENCE OF MAJOR & MINOR DEFECTS/MA Trisomy 21NormalLikelihood ratio for isolated marker* Nuchal Fold33.5%0.6%9.8* Short humerus33.4%1.5%4.1* Short femur41.4%5.2%1.6* Hydronephrosis17.6%2.6%1.0* Echogenic focus in heart28.2%4.4%1.1* Echogenic bowel13.3%0.6%3.0* Major defect21.4%0.65%5.2

###Answer: OPTION D IS CORRECT.
###Question: Which one of the following ultrasound marker is associated with greatest increased risk for Trisomy 21 in fetus
###Options:
A. Echogenic foci in heart
B. Hyperechogenic bowel
C. Choroid plexus cysts
D. Nuchal edema
