RESUMO
INTRODUCTION: Some unexplained infertile couples may have fertilization failure; the in vitro fertilization (IVF) with high insemination concentration (HIC) and intracytoplasmic sperm injection (ICSI) were reported to give better fertilization rate when compared to standard IVF procedure. OBJECTIVE: To compare the fertilization rate, abnormal fertilization rate, total fertilization failure rate, and pregnancy rate between the IVF with HIC and ICSI for the treatment of unexplained infertility. MATERIAL AND METHOD: The prospective study in 36 unexplained infertile couples in Thammasat University Hospital between 2005-2007 was performed by equally dividing sibling oocytes in assisted reproductive technology cycles with controlled ovarian hyperstimulation protocol in each patients into two groups; group I were inseminated with 200,000 sperms (IVF with HIC) and group II underwent ICSI procedure. The embryos from the better fertilization group were selected to transfer The fertilization rate, the abnormal fertilization rate, the implantation rate, the pregnancy rate and total fertilization failure rate were compared by Chi-square test and Fisher's exact test with statistical significance if p < 0.05. RESULTS: The fertilization rate, the abnormal fertilization rate, the implantation rate, the pregnancy rate and total fertilization failure rate of group I and II were 56.97% vs. 70.29% (p = 0.15), 6.56% vs. 1.26% (p = 0.003), 12.50% vs. 15.00% (p = 0.50), 38.46% vs. 36.36% (p = 0.67) and 13.89% vs. 0.0% (p = 0.04) respectively. CONCLUSION: ICSI exhibited least total fertilization failure rate (0.0% VS. 13.89%) and gave less abnormal fertilization rate (1.26% vs. 6.56%) with statistical significance in unexplained infertility when compared to the IVF with HIC procedure. Therefore, applying of ICSI procedure may increase the success chance of embryo transfer and pregnancy outcomes.