Impact of male genital tract infections on semen quality: a systematic review and meta-analysis.

Male genitourinary (GU) infections have been proposed to adversely affect semen quality and reproductive outcomes; however, existing evidence remains heterogeneous. This systematic review and meta-analysis evaluated the association between GU infections and semen parameters, reproductive outcomes, and assisted reproductive technology (ART) outcomes using control-comparator studies identified through PubMed, Web of Science, and Embase. Studies compared men with documented GU infections with noninfected controls and reported outcomes that were included consisted of semen volume, concentration, motility, morphology, antisperm antibody prevalence, natural pregnancy, miscarriage, clinical pregnancy, fertilization, and live birth outcomes. Fifty-one studies met criteria for qualitative synthesis, and 35 were included in quantitative meta-analysis. Pooled mean-based analyses demonstrated significant reductions in semen volume (mean difference [MD] -0.37 mL [95% confidence interval [CI] -0.64 to -0.09]), sperm concentration (MD -6.65 million/mL [-11.17; -2.14], heterogeneity statistics [I2] 90%), progressive motility (MD -5.93% [-9.07 to -2.78]), total sperm count (MD -47.15 million [-91.42 to -2.88]), and morphology (MD -0.76% [-1.19 to -0.33]). Total motility, vitality, and deoxyribonucleic acid (DNA) fragmentation index were not significantly different between groups. Substantial heterogeneity was observed across outcomes (I2 66%-95%). Binary outcomes were reported in five studies. Human papillomavirus infection was associated with increased antisperm antibody prevalence (OR 10.63 [1.49-75.93]), whereas most pregnancy and live birth outcomes did not significantly differ between infected and control groups. Hepatitis B virus infection was associated with an increased risk of miscarriage (OR 1.43 [1.05-1.93]). The ART-specific outcomes were limited and generally nonsignificant. Overall, GU infections were associated with impairments in select semen parameters, particularly in infertile populations. Substantial heterogeneity and predominantly observational study designs warrant cautious interpretation. Prospective studies with standardized diagnostic and reporting frameworks are needed to clarify the clinical relevance of these associations.