RESUMO
<p><b>OBJECTIVE</b>To investigate chromosomal euploidies in early-stage arrested human embryos.</p><p><b>METHODS</b>To determine the euploidy status of the 24 chromosomes, 13 embryos were analyzed, which included 5 arrested at 4-cell stage, 4 arrested at 8-cell stage, and 4 embryos at blastocyst stage regardless of their morphological scores. All embryos were subjected to biopsy, whole genome amplification, and array comparative genome hybridization analysis.</p><p><b>RESULTS</b>Chromosome euploidies of the arrested embryos can be normal, aberrant and chaotic. Mosaicism is prevalent in early stage cleavage, whilst most of the blastocysts, even with poor morphology, are normal diploid.</p><p><b>CONCLUSION</b>Arrested embryo may have normal chromosomes euploidy. Mosaicism is common in cleavage stage embryos. Early stage embryo arrest may not be solely attributable to chromosomal aneuploidies and needs further research.</p>