Introduction: The incidence of chromosomal abnormalities was investigated in untransfered embryos reuslted from in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) procedures.
Materials and Methods: A total of 238 embryos of varying morphology between the pronucleated stage and 8-cells were analysed. The cytogenetic method of Dyban was used for chromosome preparation. Embryos were kept in a medium containing 0.2mg/mL colchicine for 4-6 hrs.Then cells were transferred into watch glass contaning hypotonic solution of 1.93% sodium citrate and 0.56% KCl for 25-60 min. Cells were fixed in three different fixatives sequentially, then they were stained in 10% Giemsa and examined with a light microscope at /Far/*/Lat/1000.
Results: The cytogenetic analysis of 68 embryos resulted from IVF and 70 embryos from ICSI indicate that a total of 89.86% of embryos were cytogenetically abnormal and only 10.14% were normal. In both groups, aneuploidy was found to be the most frequent observed abnormality (43.48%). In addition to that various types of aberrations such as triploidy (2.2%), haploidy (1.5%), mosaicism (29.7%) or structural abnormalities (13.04%) were found.
Conclusion: There is a progressive loss of the embryos with chromosomal abnormalities during preimplantation development. The maternal age may have an effect on the chromosome segregation in oocytes causing aneuploid embryos. This study also shows that both healthy and morphologically unhealthy embryos can have either normal or abnormal chromosome complements; therefore the embryo morphology is not always indicative of chromosome status.