RESUMO
PURPOSE: To evaluate the role of ICSI in unexplained infertility. METHODS: In 125 cycles with six or more oocytes retrieved per cycle, sibling oocytes were randomly allocated to IVF or ICSI (group A). In 74 cycles with less than six oocytes retrieved per cycle, cycles were allocated to IVF or ICSI (group B). RESULTS: In group A, ICSI fertilization rate of 61% per allocated oocyte was higher than IVF fertilization rate of 51.6% (P < 0.001). Complete fertilization failure occurred in 19.2 and 0.8% of cycles in IVF and ICSI, respectively (P < 0.001). In group B, fertilization rate in IVF cycles was 53.3% as compared to 60.7% per allocated oocyte in the ICSI cycles (P = 0.29). Complete fertilization failure was higher (P = 0.02) in conventional IVF (34.3%) than ICSI cycles (10.3%). CONCLUSIONS: Allocation of sibling oocytes to IVF and ICSI in the first cycle minimizes risk of fertilization failure. For patients with limited number of oocytes, ICSI technique is recommended.
