MORPHOLOGICAL DEFECTS IN INTRACYTOPLASMIC SPERM INJECTION

Objective: Was to determine if severe morphological defects of spermat ozoa in Oligo-Astheno-Teratozoospermia (OAT) have any impact on the fe rtilization process in intracytoplasmic sperm injection (ICSI) and, if there are any specific morphological characteristics of unfertilized oocytes after the ICSI procedure. Methods: Ejaculates of males with se vere subfertility and unfertilized oocytes after the ICSI procedure we re investigated by transmissionelectronmicroscopy. Results: ICSI provi ded a fertilization rate of 66% in cases of severe defective spermatoz oa. The ultrastructure revealed severe head and neck alterations in pa rticular. The ultrastructure of the unfertilized oocyte displayed most ly no signs of activation and lack of decondensation of sperm chromati n. Conclusions: Our findings support the hypothesis that not severe sp erm defects but the lack of intracytoplasmic sperm-oocyte interaction displays the most critical role in the fertilization process in intrac ytoplasmic sperm injection.