Chromosomal characteristics at cleavage and blastocyst stages from the same embryos

To investigate chromosomal characteristics in the same embryos at cleavage and blastocyst stage.

Six PGD/PGS cycles were retrospective studied, including five chromosomal translocation PGD cycles and one recurrent abortion PGS cycle. The cleavage embryos were biopsied one blastomere at day 3, followed by blastocyst culture. Trophectoderm cell biopsy was performed when embryos developed into the blastocyst stage. Whole genome amplification and 24-chromosomal analysis by CGH/SNP microarray was performed on each blastomere and trophectoderm cells.

After PGD/PGS, only one couple had no euploid embryos to transfer. Five couples delivered a healthy, balanced-karyotype baby. A total of 18 embryos had both blastomere and trophectoderm cell reliable results available. Of the 18 embryos, eleven embryos contained identical chromosomes from cleavage stage to blastocyst stage and six embryos contained almost identical chromosomes . Only one embryo presented opposite chromosomal results for the cleavage and blastocyst stage, with abnormal chromosomes in the blastomere but normal chromosomes in trophectoderm cells.

Most embryos maintain chromosomal stability during embryonic development. Compared to cleavage stage, blastocyst stage may provide more reliable aneuploidy results.