Poor sperm quality affects clinical outcomes of intracytoplasmic sperm injection in fresh and subsequent frozen-thawed cycles: potential paternal effects on pregnancy outcomes.

Objective: To evaluate objectively whether poor sperm quality affects sequential events from fertilization to delivery in fresh intracytoplasmic sperm injection (ICSI) and subsequent frozen-thawed embryo transfer (ET) cycles.

Design: Retrospective study.

Setting: University-based centers for reproductive medicine.

Patient(s): For unbiased comparison, 206 cycles were chosen from 1,999 cycles of patients who underwent ICSI-ET and/or subsequent frozen-thawed ET. Cycles met the following criteria: day 3 ET; female age, <40 y; number of retrieved oocytes, >or=5; no split insemination; and no female factors but tubal factor.

Intervention(s): None.

Main Outcome Measure(s): The rates of fertilization, embryo implantation, clinical pregnancy, and delivery and sequential embryonic score (SES) were compared between normal-spermatogenesis patients (NSPs) and defective-spermatogenesis patients (DSPs).

Result(s): Although sum SES, mean SES, and top SES of transferred embryos on day 3 were similar between NSPs and DSPs, the rates of implantation, clinical pregnancy, and delivery of NSPs were significantly higher than those of DSPs. Furthermore, subsequent ET cycles with frozen-thawed embryos in NSPs and DSPs who failed to achieve pregnancy in their fresh cycles showed that rates of implantation and clinical pregnancy also were significantly lower in DSPs.

Conclusion(s): Quality of sperm may influence embryo implantation and subsequent pregnancy outcomes without impairment of embryo quality.