Decline of semen quality among 10 932 males consulting for couple infertility over a 20-year period in Marseille, France

Abstract

Semen from 10 932 male partners of infertile couples was analysed and sperm parameter trends were evaluated at the Reproduction Biology Laboratory of the University Hospital of Marseille (France) between 1988 and 2007. After 3-6 days of abstinence, semen samples were collected. Measurements of seminal fluid volume, pH, sperm concentration, total sperm count, motility and detailed morphology of spermatozoa were performed. Sperm parameters were analysed on the entire population and in men with normal total numeration (≥40 million per ejaculate). The whole population demonstrated declining trends in sperm concentration (1.5% per year), total sperm count (1.6% per year), total motility (0.4% per year), rapid motility (5.5% per year) and normal morphology (2.2% per year). In the group of selected samples with total normal sperm count, the same trends of sperm quality deterioration with time were observed. Our results clearly indicate that the quality of semen decreased in this population over the study period.

Figure 1

Linear regression lines of the means per year of the main sperm parameters. For each parameter, the graph shows the linear regression line with 95% confidence interval over the study period. The pH increases significantly with time (a). Significant decreases in mean sperm concentration (b), mean total sperm count per ejaculate (c), total motility (d), rapid motility (e) and normal morphology (f) were observed. For the morphology, results are showed until the end of 2002, because some modifications in morphological analysis were introduced from 2003. M, million.

Figure 2

Linear regression lines of the mean per year of morphological abnormalities which change significantly over the study. For each parameter, the graph shows the linear regression line with 95% confidence interval over the study period. For the percentage of spermatozoa with bent tail, results are showed until the end of 2002: (a) amorphous head; (b) multiple head; (c) bent tail; (d) tailless head; (e) headless tail; (f) multiple tail; (g) thin head; (h) cytoplasmic droplet.