Inter-sample variability in post-thaw human spermatozoa

Semen cryopreservation is a useful tool for preserving fertility in men who have been diagnosed with cancer and will undergo chemotherapy, radiotherapy or testicular surgery. Semen is also commonly cryopreserved prior to its use in assisted reproductive techniques such as in vitro fertilization and intracytoplasmic sperm injection. The post-thaw quality of banked sperm can vary, which may negatively affect fertilization rates. The objective of our study was to assess the pre-freeze and post-thaw variability of sperm parameters in patients who used our sperm banking services. Multiple samples obtained after a short period of sexual abstinence were examined for variation in sperm characteristics. Semen samples showed a high degree of post-thaw inter-sample variability in sperm motility, motion characteristics, and percentage cryosurvival rate compared with the pre-freeze inter-sample variability. Further research is necessary to understand the mechanism(s) responsible for this variability. This may also assist clinicians utilize semen samples with optimum semen quality in ART procedures.