![Sample our Bioscience journals, sign in here to start your access, Latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5925/TOC-Subject-Sample-2021-Bioscience.jpg"})
Abstract
To determine the possible changes in semen quality of Venezuelan men from 1981 to 1995, a retrospective analysis of semen volume and sperm concentrations was carried out for 2313 men from infertile couples. According to the sperm counts the sample was categorized in four groups: A, 0 sperm; B, <20 x 106 sperm/mL; C, 20-200 x 106 sperm/mL; D, 200 x 106 sperm/mL. The percentage of men in each group was 9.1, 18.8, 63.1, and 9.0%, respectively. The frequency of azoospermia and oligozoospermia (groups A and B) did not change over the last 15 years. On the contrary, the frequency showed a significant increase in group C and a decrease in group D. The range of the means of semen volume was 2.6-3.6 mL, linear regression analysis did not show a decrease in seminal fluid volume over time. The range of the means of sperm concentrations were 6.2-12.0 x 106 sperm/mL, 73 -100 x 106 sperm/mL), and 230-340 sperm x 106/mL in groups B, C, and D, respectively. Linear regression analysis revealed a significant reduction in the means of sperm concentrations only in group D. Excluding the azoospermic group, the analysis of pooled data (B + C + D), did not show a significant change in the means of sperm density throughout time. In the semen samples with sperm counts below 200 x 106/mL the means of sperm concentration did not change in the 15-year period of observation.