Sperm characteristics in normal and abnormal ejaculates are differently influenced by the length of ejaculatory abstinence

Background: No association between the length of ejaculatory abstinence (LEA) and semen characteristics has been confirmed. A short LEA has been linked to improved sperm characteristics and a higher pregnancy rate, but its negative influence on sperm chromatin maturity and longevity may adversely affect reproductive outcomes. Objectives: We sought to determine the influence of LEA on (i) semen parameters in normozoospermic and abnormal ejaculates; and (ii) the outcomes of sperm-preparation methods in a large number of subfertile men undergoing infertility workups. Materials and methods: This retrospective registry-based cohort study analyzed the data of 10,674 ejaculates from 7972 subfertile men, who were then segregated into normozoospermic, oligozoospermic, asthenozoospermic, and oligo-asthenozoospermic cohorts. Variations in semen characteristics and post-wash outcomes were studied between four LEA intervals across 0–15 days. Results: An age-adjusted analysis of covariance (ANCOVA) model linked significant increases in ejaculate volume, sperm concentration (except in the oligozoospermic cohort), and total sperm count to an increased LEA (p < 0.05). LEA was negatively associated with motility (except in the asthenozoospermic cohort) and vitality (p < 0.05). Large-headed spermatozoa were less common with an increased LEA only in the oligo-asthenozoospermic cohort (p < 0.05). In the normozoospermic cohort, a longer LEA led to fewer spermatozoa with amorphous heads but more spermatozoa with tapered heads and cytoplasmic droplets (p < 0.05). LEA extension resulted in greater sperm DNA fragmentation in the abnormal cohort (p < 0.01). The post-wash sperm concentration and total motile sperm count were significantly improved with a longer LEA in the normozoospermic cohort (p < 0.05). Discussion and conclusion: Considering the findings in this study and existing literature, a generalized recommendation for long LEA has no clinical value. The LEA should be individualized based on the ejaculate profile and the need for specific clinical intervention.