Among 409 men evaluated for infertility, current marijuana users had more than twice the odds of abnormal sperm shape and lower semen volume, but unexpectedly had lower odds of abnormal motility.
Men concerned about fertility and marijuana use, and reproductive medicine clinicians.
43% of infertility patients reported ever using marijuana
What the researchers found
Current marijuana use was associated with 2.15 times higher odds of abnormal strict morphology and 2.76 times higher odds of low semen volume. However, current users had 0.47 times the odds of abnormal motility (meaning better motility). Past users also showed higher rates of abnormal morphology (53.4%) compared to never-users (33.1%). 43% of men in the infertility clinic reported ever using marijuana.
Why it matters
With 43% of infertility patients reporting marijuana use, understanding its effects on semen quality is clinically relevant. The mixed findings (worse morphology and volume, better motility) complicate simple messaging about marijuana and fertility.
The numbers in context
409 patients. 174 (43%) ever-users: 71 current, 103 past. Abnormal morphology: 33.1% (never), 50.7% (current), 53.4% (past). Current use OR for abnormal morphology: 2.15 (95% CI: 1.21-3.79). OR for low volume: 2.76 (95% CI: 1.19-6.42). OR for abnormal motility: 0.47 (95% CI: 0.25-0.91).
How the study worked
Prospective study of 409 men presenting for infertility evaluation at one institution (July 2017-April 2018). Semen analysis performed per WHO 5th Edition criteria. Marijuana use assessed via reproductive health questionnaire. Multivariate logistic regression controlled for confounders.
What this study cannot tell us
Infertility clinic population may not represent general population. Self-reported marijuana use. Cannot determine dose-response. Retrospective questionnaire for past use. Confounders like other substance use not fully controlled.
How to read the evidence
Moderate-sized prospective study with WHO-standard semen analysis. Self-reported exposure and infertility clinic population are limitations.
When this study was published
2021 study with data from 2017-2018.
The bigger picture
The motility finding is counterintuitive and has been seen in other studies. One hypothesis involves the endocannabinoid system role in sperm function, where THC may mimic endocannabinoids that regulate sperm movement. The morphology finding is more concerning for fertility outcomes.
Questions still open
- Why does marijuana appear to worsen morphology but improve motility? Does the duration or frequency of use matter? Do the morphology changes translate to lower fertility rates? Why did past users still show elevated morphology abnormalities?
Common questions
Does marijuana hurt sperm quality?
Did past marijuana use still show effects on sperm?
Read the original research
Evaluation of the impact of marijuana use on semen quality: a prospective analysis.
Therapeutic advances in urology, 13, 17562872211032484
Citation
Hehemann, Marah C; Raheem, Omer A; Rajanahally, Saneal; Holt, Sarah; Chen, Tony; Fustok, Judy N; Song, Kelly; Rylander, Heather; Chow, Emma; Ostrowski, Kevin A; Muller, Charles H; Walsh, Thomas J. (2021). Evaluation of the impact of marijuana use on semen quality: a prospective analysis.. Therapeutic advances in urology, 13, 17562872211032484. https://doi.org/10.1177/17562872211032484
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