Chromosomal microarray analysis in 1292 fetuses with ultrasound soft markers during mid-term pregnancy.

Chromosomal microarray analysis screening for numerical abnormalities and copy number variants in fetuses with ultrasound soft markers.

Mid-trimester ultrasound soft markers may indicate a fetal chromosomal abnormality, but their predictive value remains debated. The authors retrospectively analysed 1,292 fetuses that underwent invasive prenatal diagnosis because of soft markers, grouped into one isolated marker (n = 1,039), two markers (n = 199) and three or more (n = 54). The overall incidence of chromosomal abnormality was 13.24% (171/1,292), of which 66.67% were numerical abnormalities, 29.24% pathogenic copy number variants and 4.09% likely pathogenic copy number variants. Rates rose with the number of markers, from 10.49% with one marker to 17.09% with two and 51.85% with three or more (p < 0.01), the highest rates being seen with thickened nuchal fold (26.32%), mild tricuspid regurgitation (17.86%) and absent or hypoplastic nasal bone (16.94%). On multivariable analysis, thickened nuchal fold, absent or hypoplastic nasal bone, pyelectasis and mild tricuspid regurgitation were associated with an increased risk of chromosomal abnormality.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The gradient with the number of markers is the operational message: beyond three soft markers, a risk above 50% changes the very nature of the prenatal counselling consultation. Selection bias is major, since these are fetuses already referred for an invasive procedure, and these rates are not transferable to an unselected ultrasound population. The series remains useful for ranking markers against each other, thickened nuchal fold and nasal bone anomaly standing clearly apart from isolated pyelectasis.

Analysis by Dr Thibaut Benquey