Objective: To evaluate the outcome of intracytoplasmic sperm injection (ICSI) in patients with previous idiopathic fertilization failure (< or =20% fertilization rate) after conventional IVF.
Design: Retrospective analysis.
Setting: IVF program at a university medical center.
Patient(s): Twenty-five patients who underwent 38 ICSI cycles after experiencing unexplained fertilization failure with conventional IVF (group A) and 87 patients who underwent 118 ICSI cycles for male factor indications during the same period (group B).
Intervention(s): Intracytoplasmic sperm injection was performed in a subsequent cycle after fertilization failure with conventional IVF.
Main outcome measure(s): Outcomes of IVF were compared between groups A and B.
Result(s): Fertilization was achieved with ICSI in all patients with previous fertilization failure. The mean (+/- SD) fertilization rate (68%+/-21% vs. 64%+/-22%), implantation rate per embryo (22.6% vs. 20%), and delivery rate per cycle (47.3% vs. 49.1%) did not differ significantly between groups A and B. Overall, 72% of patients with previous unexplained fertilization failure had a successful pregnancy after ICSI.
Conclusion(s): Intracytoplasmic sperm injection can overcome unexplained fertilization failure caused by a potentially occult gamete abnormality, with the same fertilization, implantation, and pregnancy rates as are seen in patients with abnormal sperm parameters.