Failed fertilization after ICSI and spermiogenic defects

ObjectiveTo evaluate the relationship between late spemiogenic events, including histone-protamine replacement, acrosome integrity, and sperm morphology, with fertilization rate after intracytoplasmic sperm injection (ICSI).DesignProspective study.SettingIsfahan Fertility and Infertility Center, Royan Institute, Tehran, Iran.Patient(s)Semen samples from 68 infertile couples undergoing ICSI at Isfahan Fertility and Infertility center were assessed during this study.Intervention(s)Semen analysis was carried out according to World Health Organization criteria. Protamine deficiency, acrosin activity, sperm morphology, and acrosome size were assessed by chromomycin A3 (CMA3) staining, gelatinolysis test, and Papanicolaou staining (strict criteria), respectively.Main Outcome Measure(s)The correlation between protamine deficiency, sperm morphology, acrosin activity, and acrosome size with each other and fertilization rate were assessed.Result(s)Percentage CMA3 positivity and mean halo diameter show a significant correlation with fertilization rate. However, no correlation was found between sperm normal morphology and fertilization rate. The mean values of acrosome size and fertilization rate were significantly different when patients were grouped for CMA3 positivity of 40%. Multiple linear regression analysis revealed that only protamine deficiency has direct effect on fertilization rate.Conclusion(s)Protamine deficiency appears to have a more significant effect on fertilization after ICSI than acrosin activity and semen parameters.