Sperm Morphology-Based Functional Assessment in Infertile Males: The Search for Potential Diagnostic Tools

Background: Male infertility affects millions of couples, accounting for 50 percent of cases. Despite such a major contribution of the male factor, it is not properly evaluated and is often overlooked in infertility assessments. Semen analysis, which is routinely performed to assess infertility status, is unable to assess the defects at the molecular level which are important to assess the fertilizing capacity of the sperm. This study aims to determine the utility of sperm function tests as biomarkers for male infertility in addition to standard semen analysis. Methods: Thirty-five men (aged 25–45 years) were recruited and divided into two groups: those with at least one altered semen parameter (infertile group) and those with normal semen parameters but unable to conceive after more than one year of unprotected intercourse (unexplained male infertility group). The DNA Fragmentation Index (DFI), Nuclear Chromatin Decondensation Test (NCDT) and Hypoosmotic Swelling Test (HOS) were used in diagnosing sperm dysfunction in both groups. The Mann–Whitney U testand Spearman’s rank correlation were used for analyzing the parameters of the groups. A p value < 0.05 was considered statistically significant. Results: While motility and vitality were nearly identical in both groups, the infertile group showed more morphological abnormalities. The DFI was higher in the unexplained male infertility group (UMI) (82%) than in the infertile group (36%). Poor decondensation capacity was present in 27% of the unexplained male infertility group and 60% of the infertile group. Both groups’ hypoosmotic swelling values fell within the usual range. Spearman correlation analysis revealed that the NCDT showed significant positive correlations with sperm vitality (r = 0.36; p = 0.02) and morphology (r = 0.53; p = 0.001). The DFI demonstrated significant negative correlations with vitality (r = −0.45; p = 0.006) and motility (r = −0.39; p = 0.01). HOS was significantly positively correlated with motility (r = 0.56; p = 0.0004) and vitality (r = 0.57; p = 0.0003). Additionally, the NCDT and DFI showed a significant inverse correlation (r = −0.33; p = 0.04). Conclusions: These findings highlight the potential of sperm function tests as valuable diagnostic tools alongside conventional semen analysis for a more comprehensive assessment of male fertility.