Systematic review of 72 observational studies (published 1985–2025) examining the association between prenatal cannabis exposure and neurodevelopmental outcomes in children from birth to 18 years, across domains including cognition, behaviour, attention/ADHD, language, motor development, executive function, and visuospatial development.
Findings were domain-specific, not global. Behavioural dysregulation (73% of studies negative), executive dysfunction (70%), and attention/ADHD-related problems (69%) showed the most consistent adverse associations. In contrast, global cognition (84% no significant association), language (92%), and motor development (60%) were largely unaffected after confounder adjustment. Stronger associations were seen with heavier or persistent use beyond maternal awareness of pregnancy, suggesting possible dose-response and timing effects.
- All studies were observational; causal inference cannot be established. - Exposure assessment varied widely—many relied on maternal self-report, risking recall bias and underreporting. - Substantial heterogeneity in outcome measures, confounder adjustment, and exposure definitions precluded meta-analysis; residual confounding (genetic, familial, psychiatric) cannot be excluded.
Counsel pregnant patients that current evidence does not support global developmental harm from prenatal cannabis use, but consistent signals exist for behavioural regulation, attention, and executive function—domains with real downstream effects on academics and mental health. Given rising THC potency and increasing use, clear evidence-informed guidance to abstain during pregnancy remains warranted.
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