In summary, conventional screening methods (ultrasound and maternal serum screening tests) remain the most appropriate choice for first-line screening for most women in the general obstetric population. Currently, several professional society guidelines (ACOG, SMFM, and NSGC) recommend that NIPT can be offered to all women regardless of age or baseline risk.
However, CVS and amniocentesis are still considered diagnostic tests for fetal aneuploidy. Currently, NIPT that employs cfDNA is not considered diagnostic. Women having a positive NIPT result should be offered conventional invasive diagnostic testing such as CVS or amniocentesis for confirmation. With an abnormal ultrasound finding that suggests an increased risk of aneuploidy, clinicians may decide to include cfDNA testing as additional evidence of possible aneuploidy, however, the patient should undergo diagnostic testing for actual confirmation.
