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.

Purpose: In industrialized countries, air pollutants levels have been monitored closely for environmental and research issues. Using Italian data, we aimed to investigate the association between air pollutants levels and semen parameters in a cohort of non-Finnish white-European men presenting for couple’s infertility. Materials and Methods: Complete demographic and laboratory data from 1,152 infertile men consecutively assessed between January 2015 and January 2018 were analyzed. Semen analyses were based on the 2010 World Health Organization reference criteria. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). We analyzed the annual average level of the three main markers of air pollution (Pm10, Pm2.5, and NO2) between 2014 and 2018. Descriptive statistics, linear and logistic regression analyses tested the association between air pollutants levels and semen parameters. Results: Of 1,152 men, 87 (7.55%) had normal sperm parameters at first semen analysis. Of 1,065 patients with abnormal semen analyses, 237 (22.25%), 324 (30.42%), and 287 (26.95%) patients presented 1, 2 or 3 abnormalities, respectively, and 217 (20.38%) were azoospermic. At linear regression analysis, Pm10, Pm2.5, and NO2 were negatively associated with sperm morphology (Pm10: β=-0.5288 µg/m3, p=0.001; Pm2.5: β=-0.5240 µg/m3, p=0.019; NO2: β=-0.4396 µg/m3, p<0.0001). Furthermore, the adjusted odds of normal sperm morphology <4% were 1.06 (95% confidence interval [CI], 1.03–1.09; p=0.007) for Pm10, 1.07 (95% CI, 1.03–1.11; p=0.007) for Pm 2.5, and 1.03 (95% CI, 1.02–1.05; p=0.001) for NO2, respectively. Conclusions In a large homogenous cohort of infertile men, Pm10, Pm 2.5, and NO2 levels were negatively associated with sperm morphology. Conversely, no clear association was observed with other macroscopic sperm parameters.