By Priyanjana Pramanik, MSc. Reviewed by Lily Ramsey, LLM Jun 24 2024

In a recent study published in Addiction, researchers investigated the impact of the Cannabis Act (CAC) and the coronavirus disease-19 (COVID-19) pandemic on substance-related disorders among pregnant women in Quebec.

Their results indicate that following the enactment of the CAC, there was a significant increase in cannabis-related diagnosed disorders, while the rates of other drug- and alcohol-related disorders remained stable.

Study:  Changes in prenatal cannabis-related diagnosed disorders after the Cannabis Act and the COVID-19 pandemic in Quebec, Canada . Image Credit: Dmytro Tyshchenko/ Background

Research on the impacts of non-medical cannabis laws (NMCL) has explored various demographics and outcomes, but there is limited focus on pregnant women.

Previous studies in the U.S. and Canada have documented increases in prenatal cannabis use following NMCL enactments.

Concerns include the negative outcomes of prenatal cannabis use, such as preterm birth and low birth weight, and the need to protect vulnerable populations like pregnant women.

While some research indicates increased cannabis use and related hospitalizations in the general population, the specific effects on substance-related disorders during the prenatal period remain unclear, particularly outside Ontario.

Additionally, the COVID-19 pandemic's influence on substance use among pregnant women adds complexity, with some studies indicating increased cannabis use. About the study

This study addressed existing research gaps by examining the impact of NMCL and the pandemic on drug- and alcohol-related disorders among pregnant women living in Quebec, leveraging its strict cannabis policies to provide insights.

Specifically, using a quasi-experimental design, researchers evaluated the impact of the pandemic and the enactment of the CAC pandemic on cannabis-, alcohol-, and drug-related diagnosed disorders among pregnant women living in Quebec from January 2010 to July 2021. Related StoriesTeens using cannabis have 11 times higher risk of developing psychotic disordersCannabis use tied to increased risk of severe COVID-19How does prenatal cannabis use affect neonatal outcomes?

The study utilized information from the Québec Integrated Chronic Disease Surveillance System (QICDSS) database, which includes comprehensive health records for nearly all residents of Quebec.

Participants were pregnant women between the ages of 15 and 49 who had received relevant diagnoses in hospital or outpatient settings.

Diagnoses were categorized using the International Classification of Diseases (ICD) codes, focusing on three periods: pre-CAC (2010–2018), CAC (2018–2020), and the COVID-19 pandemic (2020–2021).

Monthly prevalence rates per 100,000 pregnant women were calculated for each disorder category. The analysis used Fourier terms and time trends to address potential biases in the time-series data, the analysis accounted for lags, seasonality, and time trends.

Regression models based on negative binomial distributions, with adjustments for autocorrelation and seasonality, were employed to analyze the data.

Results were presented as incidence rate ratios (IRR) and 95% confidence intervals (CI) were used. Robust standard errors were applied, and time-series plots compared actual versus predicted values. Findings

The study analyzed 2,695 drug-related (excluding cannabis), 1,920 cannabis-related, and 833 alcohol-related disorder diagnoses among pregnant women in Quebec from January 2010 to June 2021.

The pooled mean monthly incidence rates, standardized for age, were 29.4, 17.4, and 10.9 per 100,000 pregnant women. Before the CAC, the monthly incidence of cannabis-related disorders increased significantly by 0.5%, while drug and alcohol-related disorders remained stable.

After the CAC, there was a 24% increase in cannabis-related diagnoses, with no significant changes in other drug or alcohol-related diagnoses. There was a non-significant 20% decrease in alcohol-related diagnoses during the period of the pandemic.

The study’s time-series analysis, which accounted for seasonality and autocorrelation, confirmed these trends, showing that stricter cannabis regulation in Quebec influenced the increase in cannabis-related diagnoses among pregnant women. Conclusions

The study concluded that the prevalence of cannabis-related disorders in pregnant women living in Quebec increased significantly after the CAC was enacted. At the same time, diagnoses related to other drugs and alcohol remained stable, with a slight, non-significant decrease in alcohol-related disorders during the pandemic.

These findings align with prior research indicating a rise in cannabis-related health issues post-legalization but highlight the distinct impact on pregnant women in Quebec compared to other regions like Ontario, where a larger increase was observed.

The study's strengths include its use of a large, representative dataset from the QICDSS and its rigorous statistical approach. However, limitations include potential misclassification bias, under-reporting, and the lack of a control group, which future research should address.

The study emphasizes the need for universal screening and targeted counseling for pregnant women who have a history of cannabis use.

Implications of these findings suggest that stricter regulations in Quebec might influence the observed trends, and there is a need for enhanced public health efforts, including mandated pregnancy warnings on cannabis packaging.

Future research should explore the broader impact of the legislation, including non-substance-related health outcomes, and consider longer-term data to understand the trends and their implications for public health policy better. Journal reference:

Nazif-Munoz, J.I., Martínez, P., Huỳnh, C., Massamba, V., Zefania, I., Rochette, L., Vasiliadis, H. (2024) Changes in prenatal cannabis-related diagnosed disorders after the Cannabis Act and the COVID-19 pandemic in Quebec, Canada. Addiction (2024). doi: