Effect of Cryopreservation on Vital and Morphological Parameters of Spermatozoa: A Laboratory-Based Investigation

Abstract

Sperm cryopreservation is a crucial procedure in Assisted Reproductive Technology (ART); however, it is known to adversely affect the quality of recovered spermatozoa. This study aimed to evaluate the impact of the freezing and thawing processes on the vital and morphological parameters of spermatozoa. The study included 40 semen samples obtained from men with normal semen parameters attending the Al-Sgaaf Center for Infertility Investigations in Mukalla, Hadhramout, Yemen, between December 2022 and March 2023. Semen samples were analyzed pre-freezing and post-thawing according to the World Health Organization guidelines. The results of the study revealed a highly statistically significant decline (p < 0.001) in sperm quality following cryopreservation. The mean total motility decreased remarkably from 63.2% to 50.6%, and sperm vitality dropped from 63.9% to 52.4%. Furthermore, normal sperm morphology was severely affected, with the total percentage of morphologically normal spermatozoa decreasing from 35.8% before freezing to 25.9% after thawing. Regarding specific sperm regions, the normal morphology of the head declined from 23.0% to 12.1%, the midpiece from 45.6% to 41.0%, and the tail from 41.5% to 35.9%. In conclusion, the cryopreservation process causes a substantial deterioration in sperm motility, vitality, and normal morphology, highlighting the urgent need to develop optimized cryopreservation protocols and better cryoprotectants to minimize cellular stress and damage during the freeze-thaw cycle