If a patient has a risk factor for a chromosomal difference, aneuploidy markers (or “soft signs”) can be assessed by ultrasound. These “markers” are not abnormalities but rather raise concern for a possible genetic difference. If no markers are seen, then the patient’s risk can be reduced. Indications for aneuploidy screening by ultrasound include an increased risk of a genetic differences but are not limited to: maternal age > 35, abnormal maternal serum screening or abnormal NIPT/ cell free DNA screening, and increased nuchal thickness > 3-3.5 mm in the first trimester.
