Lack of Improvement of Sperm Characteristics in Obese Males After Obesity Surgery Despite the Beneficial Changes Observed in Reproductive Hormones

Background Even though obesity surgery normalizes circulating testosterone concentrations in males with obesity-associated secondary hypogonadism, its impact on spermatogenesis remains controversial. We aimed to evaluate sperm characteristics in obese men after bariatric surgery as well as changes in reproductive hormones. Methods Twenty severely obese men (body mass index (BMI) ≥ 35 kg/m 2 ) were evaluated before and 2 years after bariatric surgery. The serum was assayed for insulin, leptin, kisspeptin, and inhibin B, among other hormones. Homeostasis model assessment of insulin resistance (HOMA-IR) was estimated. We used World Health Organization reference values for sperm analysis. Results After surgery, serum total testosterone, calculated free testosterone, inhibin B, and kisspeptin increased, whereas fasting insulin, HOMA-IR, and leptin concentrations decreased. Despite these improvements, sperm volume showed a small decrease after surgery, while the rest of sperm characteristics remained mostly unchanged. Abnormal sperm concentration persisted in 60% of the patients. Conclusions Sperm characteristics may not improve after bariatric surgery despite the beneficial changes of reproductive hormones.