Cytogenetic analysis in fetuses with late onset abnormal sonographic findings

To determine the rate of chromosomal cytogenetic abnormalities in fetuses with late onset abnormal sonographic findings. Retrospective cohort of women who underwent amniocentesis at or beyond 23 weeks of gestation, for fetal karyotype and chromosomal microarray analysis, indicated due to late onset abnormal sonographic findings. All 103 fetuses had a normal karyotype. Ninety-five women also had chromosomal microarray analysis (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 first or early second trimester (7.3%, P=0.46) and significantly higher than that for women who underwent amniocentesis and CMA upon request, without a medical indication for CMA (0.99%, P<0.0001). Late onset sonographic findings are an indication for amniocentesis, and if performed, CMA should be applied to evaluate fetuses with late onset abnormal sonographic findings.