Does cryopreservation of sperm affect fertilization in nonobstructive azoospermia or cryptozoospermia?

Objective To compare intracytoplasmic sperm injection (ICSI) outcomes with the use of fresh or frozen-thawed ejaculated or testicular sperm in patients with cryptozoospermia or nonobstructive azoospermia. Design Retrospective cohort study. Setting Tertiary medical center IVF unit. Patient(s) A total of 274 patients evaluated from 1999 to 2011. Intervention(s) A total of 103 patients underwent testicular sperm extraction (TESE) because of nonobstructive azoospermia, and 171 patients were diagnosed with cryptozoospermia. Main Outcome Measure(s) ICSI outcomes during the first cycle in each technique performed according to the sperm origin (testicular vs. ejaculated) and processing (frozen vs. fresh). Result(s) Forty-eight cycles with the use of frozen testicular sperm, 22 cycles with fresh testicular sperm, 66 cycles with frozen ejaculated sperm, and 138 cycles with fresh ejaculated sperm were examined. Significantly more motile sperm were found in the fresh ejaculate group compared with the frozen-thawed ejaculate group (96% vs. 88%, respectively). Furthermore, fresh ejaculated sperm were found to have better fertilization rates than frozen ejaculated sperm (64% vs. 56%, respectively). No significant difference was found between fresh and frozen-thawed testicular sperm, either in motile sperm available for ICSI or in fertilization rate (64% vs. 62% and 52% vs. 49%, respectively). Conclusion(s) In cases of cryptozoospermia, frozen-thawed ejaculated sperm is inferior to fresh ejaculated sperm in fertilization rates. However, in nonobstructive azoospermia, no major differences were found between fresh and frozen-thawed testicular sperm. Therefore, uncoupled TESE/oocyte pick-up (OPU) should be considered in NOA cases to prevent possible unnecessary ovarian stimulation and OPU when no sperm cells are detected.