Added value of chromosomal microarray analysis over karyotyping in early fetal growth restriction: A prospective observational study

Abstract

Background: Multiple factors have been associated with an increased risk of fetal growth restriction. The risk of genetic syndromes in these cases is not well established. The aim of this study was to determine the relationship between chromosomal abnormalities and early fetal growth restriction and to assess the incremental yield of genomic microarray over conventional karyotyping in fetuses with early growth restriction.Methods: A prospective observational study of early fetal growth restriction diagnosed between 2013 and 2016 in our hospital. Chromosomal microarray analysis was performed in fetuses with early growth restriction defined as a fetal weight below the 3rd percentile estimated from 19 to 28 weeks of gestation, and a normal conventional karyotype result. 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 28 enrolled pregnant women, the incidence of early fetal growth restriction was 0.30%. We diagnosed 18.5 % of pathological results by arrays, but only one case (3.7%) were diagnosed by conventional karyotype too. Incremental yield of chromosomal microarray analysis over karyotyping was 16%. We detected a 20% incremental yield of chromosomal microarray analysis over karyotyping in fetus with structural anomalies, and a 17.6% incremental yield in isolated early fetal growth restriction. Conclusions:The use of chromosomal microarray analysis provided a 16% incremental yield of detecting copy number variations in fetuses with early growth restriction and normal karyotype. Prenatal array should be part of the usual study of these fetuses, especially if there have ultrasound malformations associated.