Among 318 follicular fluid samples from IVF patients, cannabis exposure increased cannabinoid receptor expression and reduced DNA methylation enzyme expression in granulosa cells, with cannabis detection rates tripling from 4% to 12% after Canadian legalization.
Reproductive endocrinologists, IVF specialists, women of reproductive age who use cannabis
Cannabis detection in follicular fluid rose from 4% to 12% after legalization
What the researchers found
6.4% of patients tested positive for cannabis in follicular fluid. Cannabis positivity rose from 4% pre-legalization to 12% post-legalization. Only 59% of positive patients had reported cannabis use at intake. Cannabis exposure increased CB2 receptor expression in granulosa cells and reduced DNMT3b expression and global DNA methylation, effects sustained through chronic treatment in vitro.
Why it matters
Epigenetic changes in the cells surrounding developing eggs could affect oocyte quality and embryo development. The finding that cannabis alters DNA methylation in the follicular niche raises concerns about reproductive effects that may not be immediately apparent.
The numbers in context
318 follicular fluid samples; 261 IVF patients; 17 (6.4%) positive for cannabis; prevalence rose 4% to 12% after legalization; 59% of positive patients self-reported use; CB2R expression increased; DNMT3b expression decreased; global DNA methylation decreased
How the study worked
Combined in vivo cohort (318 follicular fluid samples from 261 IVF patients, measured by LC-MS/MS) and in vitro validation using naive granulosa cells treated with phytocannabinoids. Flow cytometry assessed receptor and enzyme expression; ELISA measured global DNA methylation.
What this study cannot tell us
Small number of cannabis-positive patients (n=17). Could not assess clinical outcomes due to sample size. No details on consumption mode, frequency, or timing. IVF patients may not represent the general reproductive population. In vitro conditions differ from in vivo exposure.
How to read the evidence
Novel finding with both in vivo and in vitro validation, though limited by the small number of cannabis-positive patients and inability to assess clinical outcomes.
When this study was published
Published in 2021 using 2018-2019 IVF samples.
The bigger picture
As cannabis legalization increases access for women of reproductive age, the finding that cannabis alters epigenetic machinery in the ovarian follicle adds urgency to understanding whether these molecular changes translate to clinical reproductive outcomes.
Questions still open
- Do the observed epigenetic changes translate to impaired oocyte quality or embryo development? Are the effects reversible after cannabis cessation? How does the timing and dose of cannabis exposure affect the severity of epigenetic disruption?
Common questions
Does cannabis affect fertility?
Did all patients report their cannabis use?
Read the original research
Cannabis alters epigenetic integrity and endocannabinoid signalling in the human follicular niche.
Human reproduction (Oxford, England), 36(7), 1922-1931
Citation
Fuchs Weizman, Noga; Wyse, Brandon A; Szaraz, Peter; Defer, Miranda; Jahangiri, Sahar; Librach, Clifford L. (2021). Cannabis alters epigenetic integrity and endocannabinoid signalling in the human follicular niche.. Human reproduction (Oxford, England), 36(7), 1922-1931. https://doi.org/10.1093/humrep/deab104
Explore the wider topic
- How to Talk to Your Teenager About Weed (Without Losing Them)
- My Kid's Friends Smoke Weed: A Parent's Guide
- I Smoke Weed But Don't Want My Kids To: Navigating the Hypocrisy
- Quitting Weed as a Parent: Why It Is the Hardest and Most Important Quit
- Quitting Weed as a Teen or Young Adult
- My Kid Is Smoking Weed: A Parent's Guide