title: The relationship between chromosomal abnormality in the human preimplantation embryo and development in vitro.
abstract: The relationship between the survival of the human preimplantation embryo in vitro and chromosomal abnormality was investigated by cytogenetic analysis of a total of 250 embryos of varying morphology between the pronucleate stage and the 8-cell stage. The overall incidence of chromosomal abnormality among these embryos was 49%. At the pronucleate stage (n = 46) the incidence was 65.2%, at the 2-4-cell stage (n = 126) it was 54.6%, and at the 5-8-cell stage (n = 78) it was 27.4%. Cleavage-stage embryos with poor morphology (irregular shaped blastomeres with severe extracellular fragmentation) showed a higher incidence of chromosomal abnormality (62%; 54 of 87 analysed) than those with good morphology (22.2%; 26 of 117 analysed). This study demonstrates: (i) that there is progressive loss of chromosomally-abnormal embryos during preimplantation development; and (ii) that there is an association between chromosomal abnormality and embryo morphology.
authors.affiliation: Department of Obstetrics and Gynaecology, King's College School of Medicine and Dentistry, London, UK.
authors.forename: P A
authors.initials: PA
authors.lastname: Almeida
authors.forename: V N
authors.initials: VN
authors.lastname: Bolton
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations; D046508:Culture Techniques; D047108:Embryonic Development; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy