ABSTRACT. We studied chromosomal abnormalities in arrested embryos produced by assisted reproductive technology with fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) in order to determine the best technique for evaluating chromosomal aneusomies to be implemented in different situations. We examined individual blastomeres from arrested embryos by FISH and arrested whole embryos by CGH. All of the 10 FISH-analyzed embryos gave results, while only 7 of the 30 embryos analyzed by CGH were usable. Fifteen of the 17 embryos were chromosomally abnormal. CGH provided more accurate data for arrested embryos; however, FISH is the technique of choice for screening in preimplantation genetic diagnosis, because the results can be obtained within a day, while the embryos are still in culture.

Key words: Embryos, Comparative genomic hybridization, Fluorescence in situ hybridization