Evaluation of the Association Between Body Mass Index and Semen Analysis Parameters

Introduction Male factor infertility contributes substantially to infertility burden worldwide. Excess adiposity has been proposed as a modifiable risk factor that may impair spermatogenesis through endocrine disruption, oxidative stress, and inflammatory pathways. However, evidence regarding the association between body mass index (BMI) and conventional semen parameters remains inconsistent, and data from Southeast Asian infertility populations are limited. Materials and Methods This cross‐sectional study was conducted at the Fertility Unit of Hospital Universiti Sains Malaysia. Medical records of men aged ≥18 years undergoing infertility evaluation between January 2020 and January 2025 were reviewed. BMI was calculated as weight (kg)/height 2 (m 2 ) and categorized according to World Health Organization criteria (underweight, normal, overweight, obese, and morbidly obese). Semen fluid analysis (SFA) parameters included total sperm count, progressive motility, and normal morphology, assessed according to World Health Organization 2010 reference standards. Comparisons across BMI categories were performed using analysis of variance. Pearson correlation assessed associations between BMI and semen parameters. Multivariable logistic regression was used to evaluate the association between BMI categories and abnormal SFA. Statistical significance was set at p < 0.05. Results A total of 374 men were included. Mean (SD) total sperm count, progressive motility, and normal morphology were 77.7 (70.9) million, 49.7 (22.6)%, and 62.3 (28.3)%, respectively. There were no statistically significant differences in sperm count ( F = 2.112, p = 0.079), progressive motility ( F = 1.496, p = 0.203), or normal morphology ( F = 1.221, p = 0.302) across BMI categories. A significant deviation from linearity was observed for sperm count ( p = 0.043), suggesting a nonlinear relationship across BMI groups. Conclusion BMI was not strongly associated with conventional semen parameters among men undergoing infertility evaluation. These findings suggest that BMI alone has limited clinical utility as a predictor of routine semen quality and should be interpreted within a broader assessment of male reproductive and metabolic health.