First-trimester absent nasal bone: is it a predictive factor for pathogenic CNVs in the low-risk population?

Objective: To evaluate the association of first-trimester absent nasal bone (NB) and genetic abnormalities at G-banding karyotype and chromosomal microarray analysis (CMA) according to the nuchal translucency (NT) thickness.

Methods: This is a retrospective cohort study of fetuses that underwent the first-trimester scan for the combined test at 11 to 13 weeks' gestation. Invasive test with G-banding karyotype and/or CMA was performed based on the result of the combined test or if fetal defects were detected or for patient's choice, after genetic counseling.