CYTOGENETIC ANALYSIS OF UNCLEAVED OOCYTES AFTER INTRACYTOPLASMIC SPERM INJECTION

Purpose: This work analyzes the causes of cleavage failure after intra cytoplasmic sperm injection (ICSI) and the effect of the procedure on the chromosomes of the oocytes. Methods: Ninety-seven uncleaved oocyte s from 39 patients with severe male infertility or repeated IVF failur e were fixed; 79 were analyzable. We checked the decondensation stage of spermatozoa nucleus and the chromosomal abnormalities of the oocyre s. Results: Among the fixed oocytes, the spermatozoa nucleus was prese nt in 97% of the cases, and it was undecondensed in 89% of the cases, showing no evolution at all. A low rate (2.6%) of premature chromosome condensation (PCC) of the spermatozoa and a low rate (2.5%) of female diploidy were observed. Among the oocytes that could be karyotyped, w e observed a high rare (45%) of chromosome breakage. Conclusion: ICSI fertilization failure was due mostly to the complete lack of evolution of the spermatozoa nucleus. Oocyte selection before ICSI seemed to lo wer the PCC rate. The high rate of oocyte chromosomal breakage rate ha s to be confirmed.