Effect of Bariatric Surgery on Male Infertility: An Updated Meta-Analysis and Literature Review.

PURPOSE: We aimed to perform a meta-analysis to assess the evolution of sperm parameters and some sex hormones in obese males with idiopathic infertility who underwent bariatric surgery.

MATERIALS AND

METHODS

We systematically searched MEDLINE and Embase databases for studies that documented sperm parameters and sex hormones before and after surgery.

RESULTS

Twelve studies have been included with a total of 285 patients. The heterogeneity was deemed moderate, with an I² value of 28%. The random effects model analysis indicated a statistically significant negative association between weight loss surgery and sperm concentration. The standardized mean difference (SMD) was -5.44, with a 95% confidence interval (CI) ranging from -7.65 to -3.22. The p-value was <0.0001. Twelve articles recorded the sperm volume before and after undergoing bariatric surgery. The analysis revealed no statistically significant alteration in sperm volume following surgery (SMD=-0.16, 95% CI -0.53-0.22; p=0.42). We assessed the total sperm count available in seven studies. The analysis did not prove any significant difference between groups (SMD=12.29, 95% CI -15.01-39.58; p=0.38). Evaluated in five studies, semen pH did not evolve significantly (SMD=-0.02, 95% CI -0.12-0.09; p=0.76). Also, total motility did not improve significantly (SMD=0.61, CI -2.86-4.09; p=0.73), and the included studies had a low heterogeneity (I²=29%). Following bariatric surgery, there was a significant increase in levels of both total testosterone and sex hormone-binding globulin (SHBG) (SMD=-6.40, 95% CI -9.12 to -3.67, p<0.00001 for total testosterone and -22.22, 95% CI -26.11 to -18.33, p<0.00001 for SHBG).

CONCLUSIONS

Our data suggests that bariatric surgery does not provide any benefits in terms of sperm parameters. Obesity likely affects fertility through processes that are not well understood.