Low Birth Weight is Associated with Sperm DNA Fragmentation and Assisted Reproductive Technology Outcomes in Primary Infertile Men: Results of a Cross-Sectional Study.

Purpose: To assess the relationship between clinical and semen characteristics and assisted reproductive technology (ART) outcomes with different birth weight (BW) categories in a cohort of infertile men.

Materials and methods: Data from 1,063 infertile men were analyzed. Patients with BW ≤2,500, 2,500-4,000, and ≥4,000 g were considered as having low BW (LBW), normal BW (NBW), and high BW (HBW), respectively. Testicular volume (TV) was assessed with a Prader orchidometer. Serum hormones were measured in all cases. Semen analyses were categorized based on 2021 World Health Organization reference criteria. Sperm DNA fragmentation (SDF) was tested in every patient and considered pathological for SDF >30%. ART outcomes were available for 282 (26.5%) patients. Descriptive statistics and logistic regression analyses detailed the association between semen parameters and clinical characteristics and the defined BW categories.

Results: Of all, LBW, NBW, and HBW categories were found in 79 (7.5%), 807 (76.0%), and 177 (16.5%) men, respectively. LBW men had smaller TV, presented higher follicle-stimulating hormone (FSH) but lower total testosterone levels compared to other groups (all p<0.01). Sperm progressive motility (p=0.01) and normal morphology (p<0.01) were lower and SDF values were higher (all p<0.01) in LBW compared to other groups. ART pregnancy outcomes were lower in LBW compared to both NBW and HBW categories (26.1% vs. 34.5% vs. 34.5%, p=0.01). At multivariable logistic regression analysis, LBW was associated with SDF >30% (odd ratio [OR] 3.7; p<0.001), after accounting for age, Charlson Comorbidity Index (CCI), FSH, and TV. Similarly, LBW (OR 2.2; p<0.001), SDF >30% (OR 2.9; p<0.001) and partner's age (OR 1.3; p=0.001) were associated with negative ART outcomes, after accounting for the same predictors.

Conclusions: LBW was associated with impaired clinical and semen characteristics in infertile men compared to both NBW and HBW. SDF and ART outcomes were significantly worse in the LBW group.