Prolonged sperm storage may impair reproductive capacity by reducing sperm quality despite increasing ejaculate volume. Evidence suggests that oxidative stress and cumulative DNA damage reduce motility and cellular vitality over time.

In animals, mature sperm are stored in men before ejaculation and, at times, in women before fertilization. Although this storage confers evolutionary advantages, it may also lead to deterioration through postmeiotic sperm senescence, according to a study published in Proceedings of Royal Society B. The findings described the mechanisms underlying sperm deterioration during storage and their effects before and after fertilization.

Speaking with El Médico Interactivo, part of the Medscape Professional Network, Rodrigo García-Baquero, MD, PhD, specialist in Urology and Andrology at the Puerta del Mar University Hospital, Cádiz, Spain, and spokesperson for the Spanish Association of Urology, said that “after reviewing the scientific literature, this study concludes that ejaculatory abstinence can damage sperm fertilizing capacity through senescence. In humans, abstinence, accumulation, or prolonged storage increases oxidative stress and sperm DNA damage, thereby reducing sperm motility and vitality. In animals, these effects are more pronounced, with additional effect on the fertilization process and embryo quality if the oocyte is fertilized.”

Reproductive Impact

“The study may have important implications for reproductive medicine,” he added. Longer periods of abstinence were associated with reduced quality of ejaculated sperm, suggesting that shorter intervals could improve sperm quality. This approach may be applied to attempts at natural conception and to sample collection before assisted reproductive techniques such as in vitro fertilization and intracytoplasmic sperm injection, with the aim of improving reproductive success rates.

According to this review, prolonged abstinence compromises sperm quality. “Although abstinence may increase the number of sperm in the ejaculate, their quality is clearly affected,” García-Baquero said. “This deterioration is driven by several mechanisms. Primarily, oxidative stress increases because sperm generates reactive oxygen species that damage DNA, membranes, and mitochondria. In addition, sperm has limited self-repair capacity, which is seen in most cells in the body, so cellular damage accumulates over time and increases exponentially.”

High metabolic demand, combined with limited energy reserves, further reduces sperm function because the interval to ejaculation lengthens. Minimal cytoplasm restricts antioxidant capacity. Together, these factors lead to a progressive decline in sperm quality, reflected in reduced motility and vitality, which limits reproductive capacity.

Key Factor

The study provides an integrated and quantitative perspective on male infertility by identifying sperm age, defined by storage duration, as a key determinant of sperm quality. It also highlights the specific mechanisms of damage, including oxidative stress and DNA fragmentation, which may help explain unexplained infertility cases.

These findings may support more precise and individualized diagnostic approaches. “It helps explain cases of idiopathic or unexplained infertility by considering sperm age as a relevant factor. It also suggests elevated levels of sperm DNA fragmentation and variability in sperm quality among the samples. In summary, it may contribute to understanding repeated failures in assisted reproductive techniques by identifying hidden factors related to spermatogenesis that affect fertility and improve clinical diagnosis,” García-Baquero added.

García-Baquero reported having no relevant conflicts of interest. 

This article was translated from El Médico Interactivo, part of the Medscape Professional Network.