Impact on ICSI outcomes of adding 24 h of in vitro culture before testicular sperm freezing: a retrospective study

PURPOSE: To compare sperm parameters and intracytoplasmic sperm injection (ICSI) outcomes for testicular spermatozoa frozen on the day of the biopsy (DO) with those frozen after 24 h of in vitro culture (D1). METHODS: In this retrospective study, from 1999 to 2012, forty-nine azoospermic patients were included to compare sperm (motility and viability) and outcomes (fertilization (FR), implantation (IR), pregnancy (PR) and delivery rates (DR)). RESULTS: The in vitro culture increased total motility (+2.8 %, p = 0.0161) but decreased viability (−8.3 %, p = 0.007). After 24 h of culture, the post-thaw changes in motility and viability were not significant. Twenty-six couples underwent ICSI: thirty–four ICSI were performed with spermatozoa cryopreserved at D0 and eighteen with spermatozoa frozen at D1. Cumulated IR and DR were lower for ICSI with D1 spermatozoa than with D0 spermatozoa (IR: 21.6 % with D0 vs. 9.8 % with D1, p = 0.102; DR: 27.5 % with D0 vs. 8.3 % with D1, p = 0.049). CONCLUSION: Despite improving motility, freezing spermatozoa 24 h after testicular biopsy had a potential negative effect on ICSI outcomes, notably on delivery rates. These results may be related to the detrimental impact of the additional culture on the nuclear integrity of sperm.