Microarray analysis in pregnancies with isolated echogenic bowel

Introduction: Fetal echogenic bowel is a frequent sonographic finding, demonstrated in about 1% of pregnancies. The advised evaluation of fetal echogenic bowel includes maternal serology, genetic testing for cystic fibrosis, detailed sonographic anatomic survey, and invasive prenatal testing for fetal chromosomal aberrations. The objective of our study was to evaluate the risk for clinically significant chromosomal microarray analysis (CMA) findings in pregnancies with isolated echogenic bowel. Methods: Data from all CMA analyses performed due to isolated echogenic bowel reported to the Israeli Ministry of Health between January 2013 and September 2016 were retrospectively obtained. Risk estimation was performed comparing the rate of abnormal microarray findings to the control population, based on a systematic review of 9272 pregnancies and a large local cohort of 5541 fetuses with normal ultrasound, undergoing CMA testing due to maternal request. Results: Of 103 CMA analyses performed due to isolated echogenic bowel, two (1.94%) pathogenic findings were detected (47,XYY and 16p11.2 duplication). This risk was not significantly elevated compared to the control groups. In addition, three variants of unknown significance were demonstrated. Conclusions: To our best knowledge, our study is the first report describing the rate of clinically significant copy number variants in pregnancies with isolated echogenic bowel. According to our results, it seems that pregnancies with isolated echogenic bowel do not have an increased risk for abnormal CMA compared to fetuses with no evidence of sonographic anomalies. Our findings suggest that the consideration to perform CMA analysis in such pregnancies should not differ from any pregnancy with normal ultrasound.