Comprehensive Review of 89 Studies Concludes Cannabis Should Be Avoided During Pregnancy
An overview of 89 studies and reviews found potentially harmful effects of prenatal cannabis exposure on fetal growth, some neonatal outcomes, and some later-life outcomes.
Quick Facts
What This Study Found
Across 89 included studies/reviews, prenatal cannabis exposure showed potentially harmful impacts on all fetal growth measures, some neonatal outcomes, some later-life developmental outcomes, and some maternal outcomes. Evidence for other outcomes was mixed. The authors concluded cannabis should be avoided during pregnancy.
Key Numbers
89 studies/reviews included. Harmful effects found for: all fetal growth outcomes, some neonatal conditions, some later-life outcomes, some maternal outcomes. Mixed evidence for remaining outcomes.
How They Did This
Umbrella review combining an overview of systematic reviews, evidence gap mapping, targeted review updates, and de novo synthesis, searching PubMed, MEDLINE, Embase, and CINAHL with duplicate risk of bias assessment.
Why This Research Matters
As prenatal cannabis use rises, this is the most comprehensive evidence synthesis to date. Its clear conclusion, to avoid cannabis during pregnancy, provides the strongest evidence basis yet for clinical guidance.
The Bigger Picture
This review settles the debate at the evidence level: the overall weight of research supports avoiding cannabis during pregnancy. The challenge now is translating this evidence into effective public health messaging.
What This Study Doesn't Tell Us
Cannot fully separate cannabis effects from confounders like tobacco, other substance use, and socioeconomic factors. Cannabis product types and doses vary widely. Publication bias possible. Some outcome areas had limited data.
Questions This Raises
- ?Which specific cannabinoids drive the harmful effects?
- ?Is there a safe amount during pregnancy?
- ?How can public health messaging reach pregnant cannabis users effectively?
Trust & Context
- Key Stat:
- 89 studies reviewed: prenatal cannabis harmful for all fetal growth measures
- Evidence Grade:
- Highest-level evidence synthesis (overview of reviews) with rigorous methodology provides strong conclusions.
- Study Age:
- 2025 umbrella review representing the most comprehensive pregnancy-cannabis evidence synthesis available.
- Original Title:
- The impact of using cannabis during pregnancy on the infant and mother: An overview of systematic reviews, evidence map, targeted updates, and de novo synthesis.
- Published In:
- The Australian & New Zealand journal of obstetrics & gynaecology, 65(3), 312-328 (2025)
- Authors:
- Munn, Zachary, Pollock, Danielle, Stone, Jennifer, Hasanoff, Sabira, Gordon, Andrea, Price, Carrie, Stark, Michael, Barker, Timothy Hugh
- Database ID:
- RTHC-07210
Evidence Hierarchy
Analyzes all available research on a topic using a structured method.
What do these levels mean? →Frequently Asked Questions
Is it safe to use cannabis during pregnancy?
This comprehensive review of 89 studies concluded cannabis should be avoided during pregnancy. Prenatal exposure was associated with potentially harmful effects on fetal growth, some neonatal conditions, some developmental outcomes, and some maternal outcomes.
What specific harms are linked to prenatal cannabis exposure?
All fetal growth measures (birth weight, length, head circumference) showed harmful effects. Some neonatal conditions, later-life developmental outcomes, and maternal outcomes were also affected, though evidence was mixed for other specific outcomes.
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Cite This Study
https://rethinkthc.com/research/RTHC-07210APA
Munn, Zachary; Pollock, Danielle; Stone, Jennifer; Hasanoff, Sabira; Gordon, Andrea; Price, Carrie; Stark, Michael; Barker, Timothy Hugh. (2025). The impact of using cannabis during pregnancy on the infant and mother: An overview of systematic reviews, evidence map, targeted updates, and de novo synthesis.. The Australian & New Zealand journal of obstetrics & gynaecology, 65(3), 312-328. https://doi.org/10.1111/ajo.13916
MLA
Munn, Zachary, et al. "The impact of using cannabis during pregnancy on the infant and mother: An overview of systematic reviews, evidence map, targeted updates, and de novo synthesis.." The Australian & New Zealand journal of obstetrics & gynaecology, 2025. https://doi.org/10.1111/ajo.13916
RethinkTHC
RethinkTHC Research Database. "The impact of using cannabis during pregnancy on the infant ..." RTHC-07210. Retrieved from https://rethinkthc.com/research/munn-2025-the-impact-of-using
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.