Development and Preliminary Validation of a Male‐Oriented Fertility Index in Infertile Men With Varicocele

BACKGROUND: Male infertility is usually assessed using separate parameters, while a simple integrated male-oriented tool is lacking. OBJECTIVES: To develop a Male Fertility Index (MFI), assess its association with natural conception after varicocelectomy, and perform preliminary external validation. MATERIALS AND METHODS: This two-center cohort study included 149 infertile men with clinical varicocele: 99 in the development cohort and 50 in the validation cohort. Preoperative variables were analyzed against natural conception within 12 months. ROC-derived AUCs for total progressively motile sperm count, total motility, male age, and infertility duration were used to construct the MFI. RESULTS: Natural conception occurred in 30/99 couples (30.3%). MFI values were higher in men whose partners conceived (1.44 [0.87-2.15] vs. 0.64 [0.25-1.31], p < 0.001). Conception was more frequent with MFI > 0.8 than with MFI ≤ 0.8 (44.4% vs. 13.3%, p = 0.0017). In validation, corresponding rates were 40.0% and 14.3%; AUC was 0.795 (95% CI 0.650-0.911). DISCUSSION: The MFI showed a similar association with natural conception in both cohorts, although validation was limited by sample size and incomplete assessment of female factors. CONCLUSION: The MFI may summarize male reproductive status in infertile men with clinical varicocele. Its weighting and cut-off require confirmation in larger cohorts, and its usefulness in other infertility settings remains to be established.