#83 : Human Sperm Cryo-Survival Rate

Abstract

Background and Aims: Sperm cryopreservation plays an important role in the suite of services available to fertility patients. The ability to preserve the motility and viability of human spermatozoa is a key component in delivering successful assisted reproductive technologies (ART) outcomes. Cryopreservation methods expose sperm to stress, resulting in cellular damage which consequently leads to a reduction in their survival rate. The aim of this study was to evaluate the average cryo-survival rate of semen samples frozen in a clinical setting, to help improve and manage patient expectations prior to accessing this service. Method: Pre and post sperm freeze data from patients who presented at the Genea Sydney clinic for sperm cryopreservation between 2017 and 2022 was analysed. The post-thaw survival rate for 1467 specimens was assessed by averaging the total post-thaw motility with total pre-freeze motility. Only ejaculated samples, frozen on-site, who had a raw motility calculated as well as a post-thaw motility analysis able to be performed were included in the study. Results: The range of post-thaw survival was 57% to 67% per annum over the six years of examined data, with an overall cryo-survival rate of 62%. Conclusions: The data shows a consistent recovery rate of post-thaw sperm motility over the time period analysed. Literature indicates average sperm cryo-survival rates range from 30% to 50%, and previous advice to patients has been to expect around 50% sperm survival. With this new data, Genea can revise its guidance to match the current average figure of around 60%. In addition, future internal freeze optimisation studies can use this figure as a benchmark to improve upon techniques and processes.