The impact of obesity and subsequent weight loss through bariatric surgery on male fertility

This is a comprehensive review evaluating current literature published on the impact of obesity and subsequent weight loss on male factor infertility. The prevalence of obesity is increasing worldwide, and it is projected that by 2030, >50% of all adults in the United States will be obese. Obesity, with excess adipose tissue, leads to a proinflammatory state with higher reactive oxygen species production, dysfunction of the hypothalamic-pituitary-gonadal axis, and subsequent alterations in spermatogenesis. There is growing evidence to support the negative impact of obesity on male factor fertility, specifically manifesting as reduced semen parameters. However, the male contribution to fertility goes beyond the standard semen analysis. As a result, in-depth molecular studies through metabolomics, proteomics, and epigenomics have been described to better understand male factor infertility and the impact of obesity on subfecundity. Given the obesity epidemic, there has been an increase in medically supervised weight loss programs and surgical intervention for weight loss. Bariatric surgery has become the mainstay of treatment for obesity. Early case reports documented a harmful impact of bariatric surgery on semen parameters; however, more recent prospective cohort studies identify no change in standard semen parameters after significant weight loss after bariatric surgery. Nonetheless, the clinical impact of bariatric surgery on fertility and ongoing clinical pregnancy when performed for obese male partners remains undetermined and an area for further study.