Contribution of Chromosomal Microarray Analysis in fetuses with Increased Nuchal Translucency: A Prospective Observational Study

Background: Multiple factors have been associated with an increased risk of fetuses with increased nuchal translucency. The aim of this study was to determine the relationship between chromosomal abnormalities and increased nuchal translucency and also to assess the incremental yield of genomic microarray over conventional karyotyping in these fetuses. Methods: Prospective observational study of fetuses with increased nuchal translucency (≥ p 99th percentile) between 11 and 14 weeks of gestation diagnosed between 2013 and 2017 in our hospital. We performed a descriptive analysis of the mean, the interval and the standard deviation for continuous variables and an analysis of absolute frequency and percentages for the categorical variables. Results: Among 102 enrolled pregnant women, the incidence of increased nuchal translucency was 1%. We diagnosed 9.3% of pathological results by arrays, but 3 cases (4.6%) were diagnosed by conventional karyotype too. Incremental yield of chromosomal microarray analysis over karyotyping was 6.5%. Conclusion: The use of chromosomal microarray analysis provided a 6.5% incremental yield of detecting copy number variations in fetuses with increased translucency and normal karyotype. Prenatal array should be part of the usual study in these cases, especially if there is ultrasound malformations associated.