What if the standard advice to ‘save up’ sperm for days before trying to conceive is actually undermining fertility? A sweeping meta-analysis of 115 studies covering nearly 55,000 men now shows that the longer sperm wait inside the male reproductive tract, the more their motility, viability, and DNA integrity erode.
The underlying culprits are twofold: oxidative stress and energy depletion. As sperm sit idle, reactive oxygen species accumulate while cellular fuel runs low, a double hit that accelerates ageing. The report states that sperm stored during sexual abstinence actually “ages” and deteriorates in quality.
The World Health Organization currently advises 2–7 days of abstinence before semen analysis, yet the new data hint that tighter windows may be preferable. Ejaculating within 48 hours of providing a sample improves IVF treatment outcomes compared to longer durations of abstinence.
The pattern is not uniquely human. A cross-species sweep of 56 studies spanning 30 species—from birds and bees to reptiles and mammals confirms that sperm quality drops during storage across the animal kingdom. Intriguingly, sperm degrade more slowly inside females, possibly shielded by female antioxidant secretions.
The authors note that while their findings are compelling, clinical guidelines have not yet been updated to reflect these results. Couples should interpret the tentative recommendation for shorter abstinence periods as a discussion point with their clinician, not a new protocol.
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Source: Theconversation | doi.org/10.1098/rspb.2025.3181