OP08.01: Cytogenetic analysis in fetuses with late onset abnormal sonographic findings

Abstract

We studied the rate of chromosomal cytogenetic abnormalities of fetuses with abnormal sonographic findings detected in the late second or third trimester. Retrospective analysis of all women at or beyond 23 gestational weeks at a single medical centre, who underwent amniocentesis during January 2012 to December 2015, indicated for abnormal sonographic findings that first appeared and were diagnosed at late second or third trimester. Primary endpoints were the results of fetal karyotype and chromosomal microarray analysis (CMA). 102 women with 103 fetuses underwent amniocentesis due to late onset abnormal sonographic findings. All fetuses had a normal karyotype. Ninety-five women also had CMA performed. The detection rate of abnormal CMA (5/95, 5.3%) was similar to that of women who underwent amniocentesis due to abnormal early onset ultrasound findings detected at routine prenatal screening tests during the 1st or early 2nd trimester (7.3%, p=.46) and significantly higher than that for women who performed amniocentesis and CMA upon request, without having any fetal abnormal sonographic findings or medical indication for CMA (0.99%, p<.0001). Late onset sonographic findings are an indication for amniocentesis. We suggest that if amniocentesis is performed, CMA should be applied to evaluate fetuses with late onset abnormal sonographic findings.