Frequency of sex chromosomal disomy in spermatozoa of normal and oligozoospermic Iranian patients and its effects on fertilisation and implantation rates after ICSI.

Chromosomal aneuploidy is a well-known phenomenon in human gametes including spermatozoa. Success rate of fertilisation and implantation in subfertile patients with male factor has always been shown to be very low. We tried to relate the possible impact of sex chromosomal aneuploidy in spermatozoa used for intracytoplasmic sperm injection (ICSI) on fertilisation and implantation rate. To evaluate the frequency of disomy for X and Y chromosomes in sperm samples retrieved from normal and oligozoospermic individuals, primed in situ labelling (PRINS) technique was used. Following ICSI, the rate of eight-cell embryos for each category was determined and followed up for successful implantation. Results showed a statistically significant higher frequency of disomy for all chromosomes under study in spermatozoa of oligozoospermic patients compared with normal men (P<0.01). The rate of eight-cells embryo formation was significantly lower than in normal group (P<0.01). The number of embryos transferred for both groups were nearly similar. Implantation rate for oligozoospermic patients was much lower than that of the normal group but was not significantly different (P>0.05). These results demonstrate that men especially with severe oligozoospermia have an elevated risk for chromosome abnormalities in their spermatozoa. These abnormalities might affect fertilisation and pre-embryo formation with less impact on implantation.