Successful fertilization and pregnancy after intracytoplasmic sperm injection and oocyte activation with calcium ionophore in a normozoospermic patient with extremely low fertilization rates in intracytoplasmic sperm injection cycles

Objective: To investigate the effect of calcium ionophore on the fertilization rate of a patient with normozoospermia who nonetheless exhibited a low fertilization rate in intracytoplasmic sperm injection (ICSI). Design: Case report. Setting: In vitro fertilization center. Patient(s): A male patient whose sperm, though diagnosed as normal by semen analysis, exhibited a severely low fertilization rate in ICSI cycles. Intervention(s): Oocytes were activated by calcium ionophore after ICSI. Main Outcome Measure(s): Fertilization rate after oocyte activation; ultrastructure and protein expression of the patient's sperm. Result(s): The fertilization rate of oocytes activated with calcium ionophore (12 of 15, 80.0%) was higher than that of the nonactivated oocytes (4 of 16, 25.0%). Four embryos derived from the activated oocytes were transferred, resulting in a twin pregnancy. Further investigation revealed abnormalities in the patient's sperm: many nuclear vacuoles were observed and the expression of some proteins was absent. Conclusion(s): Oocyte activation with calcium ionophore was effective at increasing the fertilization rate of dysfunctional sperm characterized by ultrastructural and protein expression anomalies.