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Maternal cannabis use in pregnancy and child neurodevelopmental outcomes


Cannabis use in pregnancy has increased1,2, and many women continue to use it throughout pregnancy3. With the legalization of recreational cannabis in many jurisdictions, there is concern about potentially adverse childhood outcomes related to prenatal exposure4. Using the provincial birth registry containing information on cannabis use during pregnancy, we perform a retrospective analysis of all live births in Ontario, Canada, between 1 April 2007 and 31 March 2012. We link pregnancy and birth data to provincial health administrative databases to ascertain child neurodevelopmental outcomes. We use matching techniques to control for confounding and Cox proportional hazards regression models to examine associations between prenatal cannabis use and child neurodevelopment. We find an association between maternal cannabis use in pregnancy and the incidence of autism spectrum disorder in the offspring. The incidence of autism spectrum disorder diagnosis was 4.00 per 1,000 person-years among children with exposure compared to 2.42 among unexposed children, and the fully adjusted hazard ratio was 1.51 (95% confidence interval: 1.17–1.96) in the matched cohort. The incidence of intellectual disability and learning disorders was higher among offspring of mothers who use cannabis in pregnancy, although less statistically robust. We emphasize a cautious interpretation of these findings given the likelihood of residual confounding.

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Data availability

The dataset from this study is held securely in coded form at ICES. While data-sharing agreements prohibit ICES from making the dataset publicly available, access may be granted to those who meet prespecified criteria for confidential access, available at The full dataset creation plan is available from the authors upon request.


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This study was supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred. Parts of this material are based on data and/or information compiled and provided by CIHI. However, the analyses, conclusions, opinions and statements expressed in the material are those of the author(s) and not necessarily those of CIHI. This study is based in part on data provided by BORN, part of the Children’s Hospital of Eastern Ontario. The interpretation and conclusions contained herein do not necessarily represent those of BORN Ontario. Funding was received from the Canadian Institutes of Health Research (D.J.C., D.E.-C., H.H., D.F. and M.W.). The funder was not involved in study design, analysis or interpretation of data. The funder was not involved in the writing of the manuscript or in the decision to publish.

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D.J.C., M.W., D.F. and H.H. contributed to the conception, design, analysis and interpretation. D.J.C. wrote the manuscript. J.D. and E.S. performed all statistical analyses with contributions from S.H. and D.F. D.E.-C., L.B. and S.W.W. contributed to data interpretation and critical revisions of the manuscript. D.J.C. served as principal investigator.

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Correspondence to Daniel J. Corsi.

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Peer review information Kate Gao was the primary editor on this article and managed its editorial process and peer review in collaboration with the rest of the editorial team.

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Corsi, D.J., Donelle, J., Sucha, E. et al. Maternal cannabis use in pregnancy and child neurodevelopmental outcomes. Nat Med 26, 1536–1540 (2020).

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