Chromosomal microarray analysis for the prenatal diagnosis in fetuses with fetal echogenic bowel: a retrospective cohort study

Fetal echogenic bowel (FEB) is often accompanied by the presence of chromosomal abnormalities. Here, we intend to evaluate the efficiency of chromosomal microarray analysis (CMA) for identifying fetal risks associated with FEB, with a focus on chromosomal abnormalities and adverse pregnancy outcomes linked to FEB. This retrospective study included a total of 446 pregnant women who underwent CMA and had intrauterine fetuses with FEB. This cohort was classified into multiple subgroups for analysis, so as to obtain the relationships among FEB in different groups, chromosome microarray results, and adverse pregnancy outcomes. For fetuses with non-isolated FEB, the pathogenicity rate and microarray abnormality rate were higher than those with isolated FEB. Surprisingly, this study found that the detection rate of pathogenic copy number variations (CNVs) in FEB during the second trimester was higher than that in the third trimester. Conversely, the detection rate of FEB with variants of uncertain significance (VOUS) in the third trimester was higher than that in the second trimester. The pathogenic CNVs in cases with combined ultrasound soft markers was higher than those without, and the more soft markers were combined, the higher the abnormal rate and pathogenic rate. The detection rate of FEB with VOUS in pregnant women with a history of adverse pregnancy outcomes was higher than those without such a history. The correlations between soft markers and FEB or gestational age (GA) at diagnosis and FEB were risk factors for abnormal CMA results in FEB cases. The correlation between GA at diagnosis and FEB was a risk factor for adverse pregnancy outcomes in FEB cases. Both the GA at diagnosis and soft markers are important factors for predicting CMA abnormalities. The correlation between the GA at diagnosis and FEB is also a risk factor for adverse pregnancy outcomes of FEB.