Relationship between morphology and chromosomal constitution in human preimplantation embryo.

In in vitro fertilization (IVF) procedures, morphologic embryo grading is the sole criteria for selection of embryos transferable in utero. Cytogenetic analysis of preimplantation embryos was performed to investigate the relationship between chromosomal status and morphologic quality of preimplantation eggs. Aneuploidy was the most frequently observed abnormality. In addition, various types of aberrations such as polyploidy, haploidy, mosaicism, and fragmentation were also found. Our results, pooled with data drawn from previous reports, demonstrated the prognostic value of the embryo grading system as a means for eliminating chromosomally abnormal embryos. In contrast, data suggested that some aspects of the IVF process might be responsible for the occurrence of these abnormalities.