Among 722 IVF patients, cannabis users (9.4%) had similar implantation and pregnancy rates as non-users, with no significant differences in any measured outcome.
People undergoing fertility treatment who use cannabis, and reproductive medicine clinicians.
No significant difference in any IVF outcome between users and non-users
What the researchers found
Implantation rates were virtually identical: 40.74% for users vs. 41.13% for non-users. Ongoing pregnancy rates were 35.2% for users vs. 29.1% for non-users (not statistically significant). No significant differences were found in oocyte yield, fertilization rate, peak estradiol, sperm quality, or embryo quality.
Why it matters
Cannabis use during fertility treatment is a growing concern as legalization expands. This study provides early reassurance that light cannabis use may not significantly harm IVF outcomes, though the evidence is far from definitive.
The numbers in context
722 patients total. 68 (9.4%) cannabis users, most light users. Implantation rate: 40.74% (users) vs. 41.13% (non-users). Ongoing pregnancy rate: 35.2% vs. 29.1% (not significant). No significant differences in any other outcome.
How the study worked
Retrospective cohort study from a single Canadian IVF center. Of 722 non-donor IVF patients, 68 (9.4%) self-reported cannabis use (most described as light use). Compared IVF outcomes between users and non-users using Mann-Whitney, chi-square, and Kruskal-Wallis tests.
What this study cannot tell us
Retrospective design. Small user group (68 patients). Self-reported cannabis use likely underestimates true prevalence. Most users were light users, so heavy use effects remain unknown. Single center.
How to read the evidence
Small user sample within a single-center retrospective study. Self-reported cannabis use is a significant limitation.
When this study was published
2021 study from a Canadian IVF center following legalization.
The bigger picture
The cannabis-fertility question remains open. While this study found no detectable harm, the small user sample (68 patients) and self-reported use data mean subtle effects could have been missed. The lack of harm signal is notable but not conclusive.
Questions still open
- Would heavier cannabis use show different IVF outcomes? Are cannabis users underreporting in clinical settings? Would a prospective study with biological verification of use reveal effects missed here?
Common questions
Did cannabis affect pregnancy rates in IVF?
Were most cannabis users in the study heavy users?
Read the original research
The relationship between cannabis use and IVF outcome-a cohort study.
Journal of cannabis research, 3(1), 42
Citation
Har-Gil, Eden; Heled, Ayala; Dixon, Marjorie; Ahamed, Abdul Munaf Sultan; Bentov, Yaakov. (2021). The relationship between cannabis use and IVF outcome-a cohort study.. Journal of cannabis research, 3(1), 42. https://doi.org/10.1186/s42238-021-00099-5
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