First-trimester ultrasound assessment of the nasal bone to screen for aneuploidy.

Increasingly, women are choosing first-trimester risk assessment for Down syndrome and other aneuploid conditions. Recent studies have suggested that adding ultrasound assessment of the nasal bone to nuchal translucency thickness and maternal serum analytes in the first trimester will improve performance. This report assesses the current literature and discusses practical issues that must be addressed before widespread implementation of nasal bone screening in the United States.