Intracytoplasmic sperm injection: Achievement of high pregnancy rates in couples with severe male factor infertility is dependent primarily upon female and not male factors

Objective: To determine the efficacy and factors affecting outcome of intracytoplasmic sperm injection (ICSI) in patients with severe male factor infertility. Design: Prospectively designed clinical trial of patients selected to participate in the study based upon the following inclusion criteria: previous total failed fertilization or unsuitable sperm parameters for conventional IVF. Setting: Tertiary care academic center. Patients: Ninety-two consecutive couples undergoing IVF therapy augmented with ICSI during April through December 1994 were studied. Main Outcome Measures: Fertilization and ongoing implantation and pregnancy rates (PRs). Results: A total of 1,163 preovulatory oocytes were manipulated, yielding a diploid fertilization rate of 60.9%; the oocyte damage rate was 13.2%. The transfer rate was 95% with 43.1% of cycles having excess embryos that were cryopreserved. Overall, the clinical and ongoing PRs per transfer were 31.9% and 26.8%, respectively. None of the sperm parameters of the original semen analysis correlated with ICSI outcome. Female age did not affect fertilization results but had a significant impact on PR (<34 years: 48.9%; 35 to 39 years: 22.9%; ≥40 years: 5.9% clinical PR per transfer). Conclusions: Intracytoplasmic sperm injection offers a new and powerful therapeutic option to treat couples with severe male factor infertility associated with a variety of sperm abnormalities. An adequate female age is a pivotal factor determining a successful outcome.