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Cannabis-Related Diagnoses Among Pregnant Women Rose 24% After Canada Legalized Non-Medical Use

Retrospective CohortModerate evidence
The takeaway

In Quebec, diagnosed cannabis-related disorders among pregnant women increased 24% following Canada's Cannabis Act, while alcohol- and other drug-related diagnoses remained stable.

Prenatal health professionals and policy researchers studying legalization effects.

24% increase in cannabis-related diagnoses among pregnant women post-legalization

What the researchers found

After the Cannabis Act took effect in October 2018, there was a significant 24% increase (95% CI: 1-53%) in cannabis-related diagnosed disorders among pregnant women aged 15-49.

Why it matters

This is among the first studies to track how cannabis legalization affected diagnosed cannabis disorders specifically among pregnant women using population-level data.

The numbers in context

24% increase post-legalization (95% CI: 1-53%); 0.5% monthly increase pre-legalization; study period: Jan 2010 to July 2022

How the study worked

Quasi-experimental interrupted time-series analysis using administrative health data from Quebec, covering pregnant women aged 15-49 from January 2010 to July 2022.

What this study cannot tell us

Cannot distinguish increased use from increased detection. Administrative data rely on clinician coding. Quebec-specific. COVID-19 overlapped.

How to read the evidence

Population-level time-series analysis but cannot distinguish use from detection.

When this study was published

Published in 2024 with data through July 2022.

The bigger picture

Whether this increase reflects more cannabis use or more clinical detection remains an open question.

Questions still open

  • Is the increase driven by more use or more disclosure?
  • Did prenatal outcomes change alongside the increase?

Common questions

Did more pregnant women start using cannabis after legalization?
The study found more diagnoses but cannot determine whether this reflects more use or more detection.
Did other substance diagnoses increase?
No. Alcohol and other drug diagnoses remained stable.

Read the original research

Changes in prenatal cannabis-related diagnosed disorders after the Cannabis Act and the COVID-19 pandemic in Quebec, Canada.

Addiction (Abingdon, England), 119(10), 1784-1791

Citation

Nazif-Munoz, José Ignacio; Martínez, Pablo; Huỳnh, Christophe; Massamba, Victoria; Zefania, Isaora; Rochette, Louis; Vasiliadis, Helen-Maria. (2024). Changes in prenatal cannabis-related diagnosed disorders after the Cannabis Act and the COVID-19 pandemic in Quebec, Canada.. Addiction (Abingdon, England), 119(10), 1784-1791. https://doi.org/10.1111/add.16564

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