{"id":20342,"date":"2025-11-29T18:43:38","date_gmt":"2025-11-29T17:43:38","guid":{"rendered":"https:\/\/drugprevent.org.uk\/ppp\/?p=20342"},"modified":"2025-12-07T18:02:54","modified_gmt":"2025-12-07T17:02:54","slug":"heavy-cannabis-use-during-pregnancy-linked-to-disruption-in-brain-growth","status":"publish","type":"post","link":"https:\/\/drugprevent.org.uk\/ppp\/2025\/11\/heavy-cannabis-use-during-pregnancy-linked-to-disruption-in-brain-growth\/","title":{"rendered":"Heavy cannabis use during pregnancy linked to disruption in brain growth"},"content":{"rendered":"

Contact: Keila DePape – <\/span>Organization: Media Relations, McGill University<\/span><\/h1>\n
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Published:\u00a0<\/span>18\u00a0<\/span>November\u00a0<\/span>2025<\/span><\/span><\/div>\n<\/div>\n

Researchers using brain imaging gain rare insight into how prenatal exposure to modern, high-THC cannabis affects brain development into adulthood<\/span><\/h1>\n
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McGill University researchers at the Douglas Research Centre have found evidence that heavy cannabis use during pregnancy can cause delays in brain development in the fetus that persist into adulthood.<\/span><\/p>\n

Using advanced MRI techniques, the team tracked the effects of prenatal cannabis exposure in mice across key developmental stages.<\/span><\/p>\n

While public health agencies caution against cannabis use during pregnancy, most supporting evidence from humans is observational. The findings add biological evidence showing how heavy use can disrupt brain growth from early development to adulthood.<\/span><\/p>\n

Published in\u00a0Molecular Psychiatry<\/i>, a Nature Portfolio journal,\u00a0the preclinical study\u00a0also reflects the higher-potency cannabis available today, helping to fill a gap in understanding its potential risks.<\/span><\/p>\n

\u201cSince cannabis legalization is relatively recent, we don\u2019t yet have long-term human data on newer THC products,\u201d said senior author\u00a0Mallar Chakravarty,\u00a0Full Professor in the Department of Psychiatry and researcher at the Douglas. \u201cOur findings offer an early glimpse of possible outcomes a decade or two down the line.\u201d<\/span><\/p>\n

Tracking brain development over time<\/b><\/span><\/h2>\n

The average THC potency in dried cannabis has risen from about three per cent in the 1980s to roughly 15 per cent in 2022, with some strains reaching 30 per cent, according to\u00a0Health Canada.<\/span><\/p>\n

To model heavy use, researchers simulated daily exposure equivalent to one or two joints containing more than 10 per cent THC during a stage comparable to the first trimester of human pregnancy.<\/span><\/p>\n

They observed developmental changes across three life stages:<\/span><\/p>\n

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  1. Late pregnancy:<\/b>\u00a0Embryos exposed to THC had smaller bodies and larger brain ventricles that signal abnormal brain development.<\/span><\/li>\n
  2. Early life:<\/b>\u00a0Newborns gained weight faster, but their brains developed more slowly, suggesting a mismatch or delay.<\/span><\/li>\n
  3. Adolescence to adulthood:<\/b>\u00a0Smaller brain volumes persisted, especially in females, who also showed more anxiety-like behaviours.<\/span><\/li>\n<\/ol>\n

    \u201cThe good news is that many of these developmental delays are subtle and could likely be offset with a supportive environment,\u201d said Chakravarty.<\/span><\/p>\n

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    3D model of the neonatal brain showing regions of reduced growth (blue) and increased growth in the ventricles (red). (Source: Lani Cupo)<\/em><\/span><\/p>\n

    A rare look across the lifespan<\/b><\/span><\/h2>\n

    The methods used provided a level of detail not often achieved in preclinical studies, the researchers explain.<\/span><\/p>\n

    \u201cThat\u2019s partly because this type of research is incredibly resource intensive,\u201d said first author Lani Cupo, who carried out the work over six years during her PhD at McGill. \u201cWe used live brain imaging to follow development across the lifespan, which isn\u2019t commonly done in mice.\u201d<\/span><\/p>\n

    Collaborators at the University of Victoria later used ultra-high-resolution microscopy to examine how brain cells changed after THC exposure.<\/span><\/p>\n

    Supporting informed choices<\/b><\/span><\/h2>\n

    The researchers note that some people use cannabis before realizing they are pregnant, while others use it to manage nausea or to cope with anxiety and depression, conditions that can also affect pregnancy outcomes.<\/span><\/p>\n

    \u201cThere is no \u2018ideal\u2019 pregnancy,\u201d said Chakravarty. \u201cThis isn\u2019t about what is good or bad, it\u2019s about giving people the information they need to make informed decisions.\u201d<\/span><\/p>\n

    A follow-up study will explore whether other forms of cannabis, such as edibles, vaping and CBD products affect the brain differently.<\/span><\/p>\n

    About the study<\/b><\/span><\/h2>\n

    \u201cImpact of prenatal delta-9-tetrahydrocannabinol exposure on mouse brain development: a fetal-to-adulthood magnetic resonance imaging study\u201d by Lani Cupo and Mallar Chakravarty et al., was published in\u00a0Molecular Psychiatry.\u00a0<\/i>It was supported by the Canadian Institutes of Health Research.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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    Source: https:\/\/www.mcgill.ca\/newsroom\/channels\/news\/heavy-cannabis-use-during-pregnancy-linked-disruption-brain-growth-368978<\/span><\/h3>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    Contact: Keila DePape – Organization: Media Relations, McGill University Published:\u00a018\u00a0November\u00a02025 Researchers using brain imaging gain rare insight into how prenatal exposure to modern, high-THC cannabis affects brain development into adulthood McGill University researchers at the Douglas Research Centre have found evidence that heavy cannabis use during pregnancy can cause delays in brain development in the […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[63,30,41,40,19],"tags":[],"class_list":["post-20342","post","type-post","status-publish","format-standard","hentry","category-brain-and-behaviour","category-cannabis-marijuana","category-drug-use-effects-on-foetus","category-prevention-research","category-usa"],"_links":{"self":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts\/20342","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/comments?post=20342"}],"version-history":[{"count":5,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts\/20342\/revisions"}],"predecessor-version":[{"id":20355,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/posts\/20342\/revisions\/20355"}],"wp:attachment":[{"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/media?parent=20342"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/categories?post=20342"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/drugprevent.org.uk\/ppp\/wp-json\/wp\/v2\/tags?post=20342"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}