Cytogenetic analysis of human preimplantation embryos following developmental arrest in vitro

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.