Abstract
According to the World Health Organization guidelines, ejaculatory abstinence (EA) of 2-7 days is recommended for semen analysis. This study aimed to determine how seminal quality may be affected by two EA periods from the same man. Seminal samples from 65 men were evaluated by conventional semen analysis and qualitative characteristics after 1 and 4 days of EA (two samples/man). The semen was qualitatively analyzed by examining oxidative activity (intracellular and seminal plasma), sperm function (acrosome integrity, mitochondrial activity, and nuclear DNA integrity), and epididymal function. As expected, samples collected after 1 day of EA showed a decrease in volume and sperm total number compared to samples collected after 4 days of EA. The sperm motility of the samples collected after 1 day of EA was better compared to samples collected after 4 days of EA. Oxidative activity measured was lower after 1 day of EA compared with those measured after 4 days of EA. With regards to sperm function, samples collected after 1 day of EA showed an increase in acrosome integrity, mitochondrial activity, and nuclear DNA integrity compared with samples collected after 4 days of EA. Epididymal function showed no difference between the two-time points. Although samples collected after 4 days of EA showed better results for sperm quantity, samples collected after 1 day of EA showed better qualitative results, including motility, oxidative activity, and sperm function. Thus, it can be concluded that sperm storage at the epididymal tail may make spermatozoa more susceptible to oxidative damage. Lay summary: According to the World Health Organization guidelines, stopping ejaculation for 2 to 7 days is recommended before sperm collection for semen analysis. However, the evidence that supports these recommendations is limited. Our study aimed to compare how sperm quality was affected in samples collected after stopping ejaculation for 1 day and 4 days (two samples per man) in a total of 65 men. Although sample collection after stopping ejaculation for 4 days showed better semen quantity (volume and sperm concentration), sample collection after stopping ejaculation for 1 day showed better sperm motility and function. If not ejaculated, sperm are stored in the epididymis tail located in the scrotum beside the testicles and our study suggests that longer sperm storage may damage sperm quality. The results from this study may be used to inform guidance for sperm collection for use in assisted reproduction techniques, and lead to an improvement in both fertilization and implantation rates.