Research suggests that the Roux-en-Y procedure might improve fertility in obese men.


WASHINGTON, D.C.—Weight loss which is achieved through Roux-en-Y gastric bypass surgery (GBS) may reverse abnormal reproductive hormone profiles in obese men, according to researchers.

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“This study suggests that gastric bypass surgery might improve fertility in obese males, but future studies must  look at sperm parameters,” said lead investigator Ahmad Hammoud, MD, visiting instructor in reproductive endocrinology and infertility at the University of Utah in Salt Lake City. “Obesity is emerging as a cause of male infertility and reduced testosterone levels.” Dr. Hammoud presented study findings here at the annual meeting of the American Society for Reproductive Medicine.


He and his colleagues recruited 64 men with a BMI of 33 kg/m2 or greater, with a characteristic hormonal profile of increased estradiol levels and decreased free and total testosterone. Of these men, 22 underwent GBS shortly after recruitment. The control group consisted of obese men who declined or were denied surgery and obese males recruited from the community. The mean age of the surgery and control groups were 47.2 and 49.9 years, respectively. The mean BMI in the surgery and control groups were 48.9 and 44.9 kg/m2.


After two years, the men who had GBS had lost an average of 119 pounds; their mean BMI dropped by 16.6 kg/m2. In the control group, the men lost an average of six pounds, and they had a mean 0.7 kg/m2 change in BMI. The men who had GBS had an increase of 310.8 ng/dL in total testosterone levels compared with just a 13.5 ng/dL increase in total testoterone levels in the control group. Weight reduction also was associated with an improvement in free testosterone levels.


Similar changes were observed in other hormonal levels as well. Estradiol levels dropped by 8.0 pg/mL in the GBS group compared with an increase of 2.0 pg/mL in the control group. Sex hormone-binding globulin levels rose by 21.6 nmol/L in the GBS group versus an increase of just 2.1 nmol/L in the control group. No significant changes in luteinizing hormone and follicle-stimulating hormone were noted.


Improvement in free testosterone levels following gastric bypass surgery was correlated with reductions in C-reactive protein and insulin levels, suggesting a possible role for inflammation.