Waiting Too Long Before a Sperm Test May Skew DNA Damage Results, Study Warns

How long a man abstains from ejaculation before giving a semen sample may be quietly distorting one of the most important tests in modern fertility medicine. A large retrospective study from Qatar, published in Frontiers in Urology, suggests that sperm DNA fragmentation, a measure of genetic damage in sperm cells that has been linked to failed fertilization, poor embryo development and pregnancy loss, rises steadily the longer sperm are stored in the male reproductive tract. The researchers conclude that abstinence periods longer than four days should be avoided when testing for sperm DNA damage, a recommendation that challenges the World Health Organization’s current guidance of two to seven days of abstinence before semen analysis.

The study, led by Ralf Henkel of LogixX Fertility in the United Kingdom and colleagues at Hamad Medical Corporation in Doha, analyzed samples from 2,782 consecutive men aged between 18 and 73 who attended the infertility unit of the Department of Urology at Hamad Medical Corporation between January 2016 and January 2018. The team measured sperm DNA fragmentation using the HaloSperm test, a sperm chromatin dispersion assay in which sperm with intact DNA produce a visible halo around the sperm head after denaturation, lysis and staining, while sperm with fragmented DNA produce no halo or only a very small one. Seminal oxidative stress was assessed with the MiOXSYS system, which reports the static oxidation-reduction potential of semen in millivolts, a proxy for the balance between reactive oxygen species and antioxidant defenses in the ejaculate.

The biological rationale behind the findings lies in the peculiar vulnerability of sperm cells. During extended periods of ejaculatory abstinence, sperm are stored in the epididymis, the coiled duct where they mature and await release. There they are exposed to reactive oxygen species for longer stretches of time. Sperm are poorly equipped to cope with such assaults: their intracellular repair mechanisms are limited, and their plasma membranes are extraordinarily rich in polyunsaturated fatty acids, which are highly susceptible to peroxidation. When lipid peroxidation occurs, it generates reactive aldehydes such as malondialdehyde and 4-hydroxy-2-alkenals, compounds that are strongly mutagenic and genotoxic and can attack the tightly packed DNA inside the sperm nucleus. The result is exactly what the study observed: more DNA fragmentation and higher oxidative stress as abstinence lengthens.

The data confirmed this pattern with striking consistency. When patients were stratified into four groups according to abstinence duration, from one to two days, three to four days, five to six days, and seven or more days, significant upward trends emerged for sperm DNA fragmentation, oxidative stress, sperm concentration, ejaculate volume and the total number of DNA-damaged sperm. Mean DNA fragmentation rose from roughly 27.8 percent in the shortest abstinence group to 34.2 percent in men abstaining for a week or more, while the total number of DNA-damaged sperm climbed from about 18.7 million to nearly 51 million. Meanwhile, total motility and sperm viability showed significant downward trends, echoing the long-established trade-off in semen analysis: longer abstinence increases sperm numbers but degrades sperm quality.

To translate these trends into clinically usable thresholds, the researchers performed receiver operating characteristic curve analyses, using the widely accepted cut-off of 20 percent DNA fragmentation to classify patients as having normal or high sperm DNA damage. This analysis yielded three significant thresholds: an abstinence period of more than four days, an age of more than 37 years, and a static oxidation-reduction potential above 59.9 millivolts. Men exceeding any of these thresholds had significantly higher odds of falling into the high-fragmentation category. Abstinence beyond four days carried an odds ratio of about 1.91, elevated oxidative stress an odds ratio of about 1.66, and age above 37 an odds ratio of about 1.74.

The compounding effect of these risk factors proved particularly consequential. When the researchers used the Cochrane-Mantel-Haenszel test to account for confounding, men older than 37 years faced roughly a two-fold higher risk of high DNA fragmentation, and men with elevated oxidative stress a 1.44-fold higher risk. But when both factors were combined, the probability of high sperm DNA fragmentation was almost three times higher than in young men with normal oxidative stress. For this subgroup, the authors suggest, a shorter abstinence period and possibly antioxidant supplementation could be considered, provided other causes of DNA damage such as genital tract infection or varicocele have been ruled out.

Multiple linear regression analysis added further nuance to the picture. When high versus normal DNA fragmentation was the outcome, age emerged as the strongest independent predictor, followed by abstinence duration and oxidative stress. When the actual percentage of fragmented sperm was modeled, oxidative stress took the top spot, followed by age and abstinence. And when the total number of DNA-damaged sperm was the dependent variable, abstinence duration dominated, with age dropping out of the model entirely. The variance inflation factors close to one indicated negligible multicollinearity, meaning each factor contributed independently rather than merely reflecting the others.

The findings land in the middle of an ongoing debate about how long men should wait before producing a semen sample. The WHO laboratory manual recommends an abstinence window of two to seven days, a range followed by the American Urological Association, the American Society for Reproductive Medicine and the European Association of Urology. The Nordic Association for Andrology and the ESHRE Special Interest Group in Andrology, by contrast, recommend a narrower window of three to four days. The authors argue that the discrepancy may reflect different purposes: the WHO guidance is oriented toward reliable measurement of basic parameters such as sperm count and motility, while the ESHRE recommendation targets the window of optimal sperm functionality for fertilization, a window that, according to this study, includes DNA integrity.

The practical implications for fertility clinics are direct. A sperm DNA fragmentation test performed after a week of abstinence could return an artificially elevated result, potentially steering clinicians toward unnecessary interventions or misinforming decisions about assisted reproduction. Conversely, the study reinforces evidence that shorter abstinence periods, in some contexts as short as two hours before sperm collection for assisted reproduction, are associated with lower fragmentation rates and favorable reproductive outcomes including fertilization, embryo development, implantation and pregnancy. The authors recommend that clinicians record and consider the abstinence period whenever they order or interpret a DNA fragmentation test, and they advise a maximum of four days of abstinence for this purpose.

The study is not without limitations. Because patients were instructed to follow WHO guidelines, only six men in the cohort had abstained for longer than seven days, limiting what can be said about very extended abstinence, although the authors note that both fragmentation and oxidative stress were already rising well before that point. As a retrospective analysis, the study also could not account for lifestyle factors that drive oxidative stress, such as smoking, obesity and diabetes. The authors call for prospective studies to confirm the benefits of standardized abstinence recommendations, particularly in specific patient groups such as men with low sperm counts or poor motility. Still, with an estimated one in six people worldwide affected by infertility at some point in their lives and roughly half of cases involving the male partner, the message that a simple scheduling choice can change the outcome of a diagnostic test is one that fertility specialists are likely to hear clearly.

Subject of Research: The effect of ejaculatory abstinence duration, age and seminal oxidative stress on sperm DNA fragmentation in male fertility diagnostics

Article Title: Association of sperm DNA fragmentation with abstinence duration, seminal oxidative stress and age: a call to consider abstinence in andrological diagnostics

Article References: Henkel, R., Arafa, M., Majzoub, A., El Bardisi, H., & Das, M. (2026). Association of sperm DNA fragmentation with abstinence duration, seminal oxidative stress and age: a call to consider abstinence in andrological diagnostics. Frontiers in Urology, 6, Article 1926391. https://doi.org/10.3389/fruro.2026.1926391

Image Credits: AI Generated

DOI: 10.3389/fruro.2026.1926391

Keywords: sperm DNA fragmentation, ejaculatory abstinence, seminal oxidative stress, male infertility, semen analysis, oxidation-reduction potential, WHO guidelines, andrology, fertility diagnostics, reactive oxygen species, paternal age, HaloSperm