Bariatric Surgery Simultaneously Improves Sperm Quality

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Bariatric surgery simultaneously improves sperm quality

Analysis of the Functional Aspects of Sperm and Testicular Oxidative Stress in Individuals Undergoing Metabolic Surgery

A prospective study was conducted in obese men following metabolic surgery (Roux-en-Y Gastric bypass) to evaluate the effect of BMI reduction on male fertility, specifically seminal analysis, sex hormone profile, sperm function and levels of lipid peroxidation.

Patients with an indication for metabolic surgery were recruited from the Surgical Gastroenterology department within the Hospital Sao Paulo, Sao Paulo Federal University and its external clinic (Gastro’s, Sao Paulo).

This included males aged 20 to 50, BMI ≥ 35.0 kg/m2 with comorbidities or BMI ≥ 40.0 kg/m2, while patients with prior urological surgery, history or presence of cancer, orchitis, urogenital infection, drug abuse, excess alcohol consumption (one or more standard drink per day) and fever (within 90 days) were excluded from the study.

Overall 15 males who met the inclusion / exclusion criteria participated in the study with samples collected before surgery and after surgery, at 3, 6, 9 and 12 months post-surgery.

Semen samples were collected following 2 to 7 days of abstinence, with blood samples taken the same day. Roux-en-Y Gastric bypass (RYGB) surgery was performed by videolaparoscopy. All patients presented as their own controls in this study.

Initial analysis showed a significant reduction in BMI following surgery, with a significant increase in semen volume (2.0 to 3.0 mL, 12 months post-surgery), normal sperm percentages (4.9 to 7.6%, 6 months post-surgery) and progressive motility (43.1 to 59.2%). Subsequently a significant decrease in the percentage of immotile sperm was also seen (37.2% vs 49.5%) 9 months onwards post-surgery.

Hormone analysis showed similar improvements across the board, with significant increases in luteinizing hormone levels (3.4 vs 2.4 mUI/mL), sex hormone-binding globulin (41.1 vs 27.7 nmol/L), free testosterone (7.4 vs 5.2 ng/dL) and total testosterone (417.3 vs 263.8 ng/dL), while estradiol levels dropped significantly (38.2 to 28.3 pg/mL) 12 months post surgery.

Interestingly all 7 of the 15 males originally diagnosed with obesity hypogonadism (total testosterone < 241 ng/dL) pre-surgery, were no longer defined with hypogonadism 12 months post-surgery.

Similarly, Comet testing showed an overall improvement in the DNA integrity of sperm, with an increase in the percentage of higher grades (Comet I, Comet II) of DNA integrity sperm and subsequent decrease in lower grades (Comet III, Comet IV).

GradePre-surgery (%)12 months post-surgery (%)
Comet I24.047.3
Comet II22.138.2
Comet III34.810.7
Comet IV19.13.8

Mitochondrial activity of sperm also improved, with oxidation of the 3,3′-diaminobenzidine (DAB) testing showing an increase in Class I (complete mitochondrial activity) and Class II (some loss of mitochondrial activity without severe impairment of motility and fertilization capacity) cells and subsequent decrease of Class III (extensive loss of mitochondrial activity and unlikely to achieve hypermotility during capacitation) and Class IV (dead or minimal energy production through glycolysis) cells.

GradePre-surgery (%)12 months post-surgery (%)
DAB I7.115.4
DAB II48.667.1
DAB III22.411.4
DAB IV21.96.1

Finally lipid peroxidation levels also improved significantly 6 months post surgery (21.9 vs 27.9 ng/mL) which was found associated to the likewise reduction in BMI.


Indicators of male fertility improved following weight loss, induced by Roux-en-Y Gastric bypass surgery, with a significant increase in total testosterone (417.3 vs 263.8 ng/dL) and decrease in estradiol levels, which increased sperm progressive motility, DNA integrity & mitochondrial activity.


  1. Small study size

Similar studies

Calderón B, et al. (2019). Lack of Improvement of Sperm Characteristics in Obese Males After Obesity Surgery Despite the Beneficial Changes Observed in Reproductive Hormones.

Samavat J, et al. (2018). Massive Weight Loss Obtained by Bariatric Surgery Affects Semen Quality in Morbid Male Obesity: a Preliminary Prospective Double-Armed Study.

El Bardisi, et al. (2016). Effect of bariatric surgery on semen parameters and sex hormone concentrations: a prospective study.

Reis L O, et al. (2012). Bariatric surgery does not interfere with sperm quality–a preliminary long-term study.


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