THE PRESENCE OF MULTINUCLEATED BLASTOMERES IN HUMAN EMBRYOS IS CORRELATED WITH CHROMOSOMAL-ABNORMALITIES

The purpose of the present study was to determine whether the presence of one or more multinucleated blastomeres during early embryonic deve lopment is associated with chromosomal abnormalities in sibling blasto meres of that embryo, Embryos with multinucleated cells (n = 47) detec ted on day 2 or 3 of development were compared to dividing embryos wit hout multinucleation, Arrested embryos were excluded from this study, Chromosome abnormalities were detected using fluorescent in-situ hybri dization (FISH) with X, Y, 18 and 13/21 chromosome-specific probes. Of 47 embryos included in this study, 76.6% were chromosomally abnormal, compared to 50.9 % in the control group (P < 0.001), Excluding aneupl oidy, which is originated in the gametes and not the embryo, the diffe rences were even higher, with 74.5% of multinucleated embryos being ch romosomally abnormal compared to 32.3% of non-multinucleated embryos ( P < 0.001), Day of multinucleation appearance, number of nuclei per ce ll, number of multinucleated cells per embryo and developmental qualit y of the embryos as well as the type of fertilization (intracytoplasmi c sperm injection versus standard insemination) were not found to affe ct the rate of chromosomal abnormalities in embryos with multinucleate d cells, These results suggest that embryos with multinucleated cells may not be suitable for replacement and should be excluded unless no o ther embryos are available.