In-utero cannabis exposure was not associated with ADHD risk in a Quebec birth cohort
In a cohort of 2,408 children followed up to 17 years, occasional or regular in-utero cannabis exposure was not significantly associated with the risk of developing ADHD.
Quick Facts
What This Study Found
After adjusting for potential confounders, no significant association was found between in-utero cannabis exposure (occasional: OR 1.22, 95% CI 0.63-2.19; regular: OR 1.22, 95% CI 0.42-2.79) and the risk of ADHD in children.
Key Numbers
2,408 children met inclusion criteria. 86 (3.6%) were exposed to cannabis in utero. 241 (10.0%) had ADHD diagnosis or medication. Neither occasional nor regular exposure was significantly associated with ADHD after adjustment.
How They Did This
Cohort study using the Quebec Pregnancy Cohort. Questionnaires mailed to mothers of singleton live births between 1998-2003. Cannabis exposure based on maternal self-report during pregnancy. ADHD defined by diagnosis or prescription through provincial databases. Follow-up through December 2015.
Why This Research Matters
Given increasing prenatal cannabis use and widespread concern about neurodevelopmental effects, this null finding from a well-designed cohort adds important nuance to the evidence base.
The Bigger Picture
This finding contrasts with animal studies showing neurodevelopmental effects of prenatal THC and adds to the mixed human evidence. The question of whether prenatal cannabis exposure affects child development remains open.
What This Study Doesn't Tell Us
Cannabis exposure was self-reported by mothers and may be underreported. Relatively small number of exposed children (86). Could not account for dose, timing within pregnancy, or cannabis potency. Confounders may remain uncontrolled.
Questions This Raises
- ?Would larger samples or higher-potency cannabis exposure show different results?
- ?Do other neurodevelopmental outcomes (besides ADHD) show associations?
- ?Is the self-report underestimation masking a true effect?
Trust & Context
- Key Stat:
- No significant association for occasional or regular exposure
- Evidence Grade:
- Moderate: administrative data linkage with long follow-up, but self-reported exposure and limited exposed sample.
- Study Age:
- Published in 2022.
- Original Title:
- Is in-utero exposure to cannabis associated with the risk of attention deficit with or without hyperactivity disorder? A cohort study within the Quebec Pregnancy Cohort.
- Published In:
- BMJ open, 12(8), e052220 (2022)
- Authors:
- Tchuente, Vanina, Sheehy, Odile, Zhao, Jin-Ping, Gorgui, Jessica, Gomez, Yessica-Haydee, Berard, Anick
- Database ID:
- RTHC-04260
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Does this mean cannabis is safe during pregnancy?
This study only examined one outcome (ADHD) and found no association. It does not address other potential risks of prenatal cannabis use, and the small number of exposed children limits statistical power.
How was ADHD measured?
ADHD was identified through provincial health databases using either a medical diagnosis code or a prescription filled for ADHD medication, providing objective rather than self-reported outcome data.
How long were children followed?
Children born between 1998-2003 were followed through December 2015, allowing up to 17 years of follow-up to capture ADHD diagnoses that may emerge at school age.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-04260APA
Tchuente, Vanina; Sheehy, Odile; Zhao, Jin-Ping; Gorgui, Jessica; Gomez, Yessica-Haydee; Berard, Anick. (2022). Is in-utero exposure to cannabis associated with the risk of attention deficit with or without hyperactivity disorder? A cohort study within the Quebec Pregnancy Cohort.. BMJ open, 12(8), e052220. https://doi.org/10.1136/bmjopen-2021-052220
MLA
Tchuente, Vanina, et al. "Is in-utero exposure to cannabis associated with the risk of attention deficit with or without hyperactivity disorder? A cohort study within the Quebec Pregnancy Cohort.." BMJ open, 2022. https://doi.org/10.1136/bmjopen-2021-052220
RethinkTHC
RethinkTHC Research Database. "Is in-utero exposure to cannabis associated with the risk of..." RTHC-04260. Retrieved from https://rethinkthc.com/research/tchuente-2022-is-inutero-exposure-to
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.