A retrospective comparison of pregnancy outcome following conventional oocyte insemination vs intracytoplasmic sperm injection for isolated abnormalities in sperm morphology using strict criteria.

Initial in vitro fertilization (IVF)-embryo transfer studies found poor fertilization and pregnancy rates following conventional fertilization of oocytes when using sperm with <4% normal morphology using strict criteria. Some consider today that sperm with only < or =5% normal morphology using strict criteria are associated with infertility. However, other studies have disputed the diagnostic potential of low strict morphology in identifying subnormal male fertility. Based on the original studies most IVF centers perform intracytoplasmic sperm injection (ICSI) when the sperm shows low morphology using strict criteria to allow selection of normal sperm. However, ICSI adds extra time for the embryologist and extra expense for the infertile couple. The present study retrospectively compared fertilization, pregnancy, and implantation rates according to the 2 methods of oocyte fertilization with sperm having normal morphology using strict criteria of < or =5% in women < or =39 years. All fresh embryo transfers were performed on day 3. There was a significantly higher fertilization rate with ICSI. However, there were significantly higher clinical and delivered pregnancy and implantation rates following conventional insemination. The rate of canceled transfers due to no available embryo was 1.9% with conventional insemination vs 1.5% for ICSI in women with adequate egg reserve. Hopefully, this retrospective study will generate interest in a prospective study.