RESUMEN
OBJECTIVE: The purpose of this study was to determine whether intracytoplasmic sperm injection(ICSI) could overcome the defects of oocytes in IVF-ET patients with previous fertilization failure by conventional fertilization technique. Design: Retrospective study Materials and METHODS: A total of 119 ICSI cycles in 57 IVF-ET patients performed from May, 1995 to December, 1997 was enrolled. Subjects were divided into two groups: FR group included 66 ICSI cycles in 35 patients with normal sperm who underwent ICSI due to past history of failed or poor fertilization in the previous IVF-ET cycles, and OAT group included 53 ICSI cycles in 22 patients with severe oligoasthenoterato- zoospermia(OAT) which was defined as sperm concentration < 20 million/ml, mo#dlity < 30% and normal morphology < 4% by strict morphologic criteria. The outcomes of ICSI were analyzed and compared in both groups. RESULTS: The age of female patients, basal serum FSH level, and the numbers of oocytes retrieved and metaphase II oocytes were all comparable in both groups. The fertilization rate after ICSI was similar in both groups(68.7+/-25.3% vs. 67.7+/-24.5%), as were the cleavage rate of normally fertilized oocytes(93.1+/-21.4% vs. 89.3+/-21.6%), the number of embryos transferred(4,00+/-1.98 vs. 4.64+/-2.10), and cumulative embryo score(CES) indicating the quality of embryos(47.3+/-33.2 vs. 54.1+/-33.2). The implantation rate(4.3+/-10.5% vs. 3.8+/-11.0%) and the clinical pregnancy rate per cycle(15.2% vs. 13.2%) were also comparable in both groups. CONCLUSIONS: Although it has been shown that there is a higher risk of chromosomal abnormalities in oocytes from IVF-ET patients with pevious failed or poor fertilization, higher implantation and clinical pregnancy rates wer#e not observed in patients with OAT following ICSL Therefore, the functional defect of sperm such as loss of capacitation, defect of aaasome reaction, and abnormality of nucleus decondensation should be also considered in patients with previous failed or poor fertilization.