Disturbed sleep is a key correlate of poor sperm quality.A large real-world study presented at ESHRE 2026 shows an association between short sleep duration, sleep apnoea, and poor sperm quality.
In the multivariable logistic regression analysis, sleep apnoea was an independent predictor of reduced sperm motility or asthenozoospermia (odds ratio [OR], 1.40, 95 percent confidence interval [CI], 1.02–1.92), while sleep restriction was independently associated with abnormal sperm morphology or teratozoospermia (OR, 1.97, 95 percent CI 1.01–3.92) after adjusting for potential confounders.
Other factors affecting sperm parameters
Other factors that increased the odds of asthenozoospermia were varicocele, prior urological surgery, and medication intake excluding vitamins and supplements (ORs, 1.96, 2.62, and 1.33, respectively). For teratozoospermia, another independent predictor was tobacco smoking (OR, 2.16). [ESHRE 2026, abstract L26/P-031]
The odds of low sperm count or oligozoospermia were higher with varicocele (moderate: OR, 2.08, 95 percent CI, 1.60–2.71; severe: OR, 2.23, 95 percent CI, 1.74–2.85). Other factors that increased the odds of severe oligozoospermia were prior urological surgery (OR, 2.87, 95 percent CI, 2.05–4.04) and medication intake excluding vitamins and supplements (OR, 1.36, 95 percent CI, 1.11–1.67).
Study characteristics
There is insufficient evidence elucidating the association between semen parameters and lifestyle, comorbidities, and sleep-related variables, noted the researchers from Huntington Medicina Reprodutiva – Eugin Group, São Paulo, Brazil, at ESHRE 2026.
“Robust data from real-world fertility populations are needed to identify factors most strongly associated with abnormal sperm quality and to guide targeted counselling and risk-reduction strategies,” they said.
The investigators retrospectively evaluated 3,376 semen samples from 2,280 men undergoing fertility evaluation at two assisted reproduction centres between 2024 and 2025. Each participant completed a standard questionnaire on health, lifestyle, and sleep-related factors at the time of sample collection.
The mean age was 40.6 years. Regarding sleep-related factors, 40 percent of the participants reported snoring, 9.5 percent reported suspected/confirmed sleep apnoea, while 7.8 percent had sleep restriction.
Approximately two-thirds (62 percent) of the participants reported engaging in regular physical activity, 12.6 percent used electronic cigarettes, 7.5 percent smoked tobacco, and 4.3 percent had moderate/high alcohol intake. One-third of participants reported chronic medication intake, 19.2 percent had a history of varicocele, and 6.7 percent had prior urological surgery.
About 15 percent had a ‘severe’ sperm count (0–5 million/mL), 12.1 percent were classified as having a ‘moderate’ sperm count (5–15 million/mL), while the rest had a normal sperm count (≥16 million/mL). Seventeen percent had asthenozoospermia (progressive motility <30 percent). In men with morphology data (n=3,091), 43.9 percent had ≤1 percent of normal forms.
Sleep screening in male fertility workups
“This large real-world cohort highlights disturbed sleep (short sleep duration and sleep apnoea), alongside varicocele, chronic medication intake, prior urological surgery, severe obesity, and smoking, as key correlates of impaired sperm concentration, motility, or morphology,” the researchers said.
However, the retrospective, cross-sectional design precludes causal inference, and the self-reported exposures are subject to recall and reporting bias, they pointed out.
Residual confounding is also possible, and generalizability of the findings may have been limited as the results came from fertility clinic attendees only. Furthermore, the semen parameters were based on single samples for most men, the researchers added.
Nonetheless, the results underpin the importance of incorporating sleep screening and routine lifestyle into male fertility workups to enhance counselling and guide targeted risk-reduction strategies, they said.