The Influence of Cryopreservation on Sperm Morphology and Its Implications in Terms of Fractions of Higher-Quality Sperm

Male infertility is a significant global health issue, comprising approx. 50% of all infertility cases. Semen cryopreservation, a critical component of assisted reproductive technologies (ARTs), is a method commonly used in a wide range of situations, including gonadotoxic treatments such as radiation or chemotherapy, hazardous occupational exposures, and various medical conditions. Although historically viewed as potentially damaging to sperm, recent findings suggest that cryopreservation, when performed with appropriate techniques, may in fact enhance semen quality by improving the proportion of healthy spermatozoa, particularly in terms of their morphological parameters. The aim of this study was to evaluate the impact of cryopreservation on sperm morphology and viability, utilizing advanced morphological assessments pre- and post-freezing. Semen samples were collected from 97 patients undergoing infertility treatment at the KRIOBANK clinic (Białystok, Poland). The semen was liquefied and prepared in the form of slides. Sperm morphology was then assessed using an OLYMPUS BX40 microscope at 60× magnification. The findings of the study revealed significant improvements in sperm morphology, with increased percentages of normal sperm and reductions in deformation indices post-thaw. The findings indicate that optimized cryopreservation protocols may support the selection of higher-quality sperm, offering valuable benefits for ART applications. These results challenge certain past assumptions regarding the impact of cryopreservation and underscore the need for refined freezing techniques to maintain and potentially enhance semen quality for reproductive use.