Nuchal translucency thickness measurements for fetal aneuploidy screening: Log NT-MoM or Delta-NT, performer-specific medians and ultrasound training (original) (raw)

Objectives: To evaluate in fetal aneuploidy screening the desirability of using Fetal Medicine Foundation (FMF) normal medians of nuchal translucency thickness (NT) measurements or performer-specific medians, and whether the NT measurements should be expressed as Delta-NT or Log NT-MoM values. Settings: First trimester-combined screening programme in a low risk population in Flanders, Belgium (Algemeen Medisch Laboratorium, Antwerp). Methods: Pregnancies unaffected by trisomy 21 (T21) were screened by FMF-trained or other ultrasonographers. Performer-specific NT medians were established for FMF-trained and other ultrasonographers. NCSS Statistical Software was used to establish probability plots for Log NT-MoM and Delta-NT values, relative to performer-specific references or to the FMF-reference. Results: A total of 16,096 pregnancies were evaluated. Six FMF-trainees and five other ultrasonographers each performed between 83 and 658 NT measurements. For the FMF-trainees, FMF-specifi...