Most impoant feature to diagnose fetal aneuploidy:
Absent nasal bone
Nuchal translucency
Increase in frontomaxillary angle
Reversal of ductus venosus flow
Nuchal translucency evaluation represents the maximum thickness of the subcutaneous translucent area between the skin and soft tissue overlying the fetal spine at the back of the neck . It is measured in the sagittal plane between 11 and 14 weeks. When the nuchal translucency is increased, the risk for fetal aneuploidy and various structural anomalies--including hea defects--is significantly elevated.
Prenatal Diagnosis