Trends in Semen Quality: A Contrasting Perspective From a Single‐Centre Review in Ireland

INTRODUCTION: Male factor contributes up to half of infertility cases and reports of a global decline in semen quality raise concern for the future of male reproductive health. However, fertility trends can vary by region and population. Interpreting local patterns is crucial for understanding the true trajectory of male fertility. We describe longitudinal trends in semen parameters among men attending a single fertility clinic in Ireland. METHODS: We retrospectively analysed 18,219 semen analyses for 15,413 men attending a fertility clinic between 2008 and 2023. Sperm concentration, progressive motility and total motile sperm count (TMSC) were analysed, with 2021 WHO criteria applied to identify subnormal results. Non-parametric tests were applied to assess temporal changes (Kruskal-Wallis with Dunn's post-hoc test for multiple comparisons). A longitudinal subanalysis compared first and last semen samples among men with repeat testing, and grouped by time interval (5 years). RESULTS: Median sperm concentration increased significantly from 57 M/mL in 2008 to 70 M/mL in 2023 (p < 0.0001), representing a 22.8% rise. TMSC showed a slight, non-significant rise, while progressive motility remained stable over time. The proportion of oligospermic (