Iranian temporal changes in semen quality during the past 22 years: A report from an infertility center

Background: Despite numerous reports about temporal changes in semen quality from all over the world, the debates continue. The latest systemic review has shown an overtime decrease in semen quality worldwide.
Objective: To assess the temporal changes in the semen quality among Iranian population referred to an infertility center.
Materials and Methods: In this retrospective cross-sectional study, semen parameters including concentration, motility, and morphology were compared between Iranian men reffered to Research and Clinical Center for Infertility, Yazd between 1990 to 1992 (group 1, n = 707) and 2010 to 2012 (group 2, n = 1108). Demographic characteristics and semen analysis were collected from the records. The effect of age on semen parameters was also investigated.
Results: Despite the increase in sperm concentration l in group 2, sperm with normal morphology decreased significantly (p < 0.001). Grade-A motility decreased (p < 0.001), grade B motility increased (p < 0.001), and grade C and D motile sperm remained constant (p = 0.303 and p = 0.315, respectively). Also, no significant correlation between the age and semen parameters were observed.
Conclusion: This study showed inconsistent temporal changes in the participant semen quality. Significant temporal decline were obtained between various semen parameters, sperm morphology and grade A motility. These results should be further evaluated by larger studies in the future.