Abstract:
The relationship between chromosomal abnormalities in the humanpreimplantation embryo and developmental arrest in vitrowas investigated. Cytogenetic analysis of 171 embryos that had arrestedbetween the pronucleate and the 8-cell stages demonstrated that the overallincidence of chromosomal abnormality among these embryos was 63.4%. Ofthe embryos that arrested at the pronucleate stage (n= 48), 47.9% were chromosomally abnormal, compared with59.5% of those that arrested between the 2- and 4-cell stages(n = 50), and 82.8% of those arrestedbetween the 5- and 8-cell stage (n = 73). Therate of abnormality in embryos with poor morphology (irregular shapedblastomeres and considerable extracellular fragmentation) was significantlyhigher (86.8%; n = 33) than those withgood morphology (60%; n = 51;P<0.005). These results suggest that there is anassociation between chromosomal abnormality, developmental arrestin vitro, and poor morphology.