Chau MHK, Cao Y, Kwok YKY, et al. - Researchers sought to determine the spectrum and characteristics of pathogenic copy number variants in prenatal genetic diagnosis. In addition, they aimed at providing recommendations for expanding the scope of noninvasive prenatal screening for microdeletions and microduplications. In this retrospective study of 1,510 pregnant women who underwent invasive prenatal diagnostic testing by chromosomal microarray analysis, they identified 375 of 23,865 fetuses (1.6%) that carried pathogenic copy number variants for any indication for invasive testing; of these, 44 (11.7%) involve 2 or more pathogenic copy number variants. The fetuses exhibited a total of 428 pathogenic copy number variants, of which 280 were deletions and 148 were duplications. Three hundred sixty (84.1%) were less than 5 Mb in size and 68 (15.9%) were between 5 and 10 Mb. Collectively, findings suggest a common occurrence of pathogenic copy number variants in pregnancies. They recommend offering invasive testing in high-risk pregnancies with chromosomal microarray analysis for the most comprehensive investigation. Careful consideration of detection limits on size, parental inheritance, and genomic distribution is emphasized before implementing copy number variant screening in expanded noninvasive prenatal screening.