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Study breakdown

Cannabis use during pregnancy linked to prematurity and smaller babies in French hospital data

Retrospective CohortModerate evidence
The takeaway

In a French hospital cohort, recreational cannabis use during pregnancy was associated with increased rates of prematurity, small-for-gestational-age babies, and other adverse outcomes compared to tobacco-only users and controls.

Obstetricians, prenatal care providers, perinatal epidemiologists

Cannabis use associated with prematurity and small-for-gestational-age births

What the researchers found

Among 669 pregnancies analyzed (123 cannabis users, 191 tobacco-only, 355 controls), cannabis use during pregnancy was associated with increased voluntary interruption of pregnancy, at least one adverse event during pregnancy, at least one neonatal adverse event, prematurity, and small-for-gestational-age births. Cannabis users were younger (mean 25.5 years), had more psychiatric history (17.5%), and were more likely to have universal free healthcare coverage.

Why it matters

This study from a French hospital system provides European data on prenatal cannabis effects, complementing the predominantly North American literature and controlling for concurrent tobacco use.

The numbers in context

123 cannabis ± tobacco users, 191 tobacco-only, 355 controls; cannabis users mean age 25.5 ± 5.7 years; BMI 22.8 ± 5.5; 17.5% psychiatric history; 18.2% universal free healthcare coverage

How the study worked

Retrospective analysis of data from the Poitiers University Hospital clinical data warehouse from 2010-2019. Logistic regression compared outcomes across three groups: cannabis with or without tobacco, tobacco alone, and controls.

What this study cannot tell us

Retrospective design with data from a single hospital. Cannabis use likely underreported in medical records. Cannot fully separate cannabis effects from tobacco, socioeconomic factors, or psychiatric comorbidities.

How to read the evidence

Ten-year hospital cohort with regression analysis controlling for tobacco, but retrospective design and likely underreporting of cannabis use are limitations.

When this study was published

Published 2023 using 2010-2019 data

The bigger picture

As cannabis normalization spreads globally, data from non-North American settings helps establish whether adverse pregnancy outcomes are consistent across different populations and healthcare systems.

Questions still open

  • Are the adverse outcomes driven by cannabis itself, concurrent tobacco use, or socioeconomic factors? Would prospective studies with biological verification of exposure produce different results?

Common questions

Does cannabis use during pregnancy affect birth outcomes?
In this French hospital study, cannabis use during pregnancy was associated with increased rates of prematurity, small-for-gestational-age babies, and other adverse pregnancy and neonatal events.
How did cannabis-using mothers differ from non-users?
Cannabis users were younger (average age 25.5), had lower pre-pregnancy BMI, more psychiatric history (17.5%), and were more likely to have universal free healthcare coverage.

Read the original research

Maternal, Fetal and Neonatal Outcomes Related to Recreational Cannabis Use during Pregnancy: Analysis of a Real-World Clinical Data Warehouse between 2010 and 2019.

International journal of environmental research and public health, 20(17)

Citation

Bouquet, Emilie; Blouin, Pascal; Pérault-Pochat, Marie-Christine; Carlier-Guérin, Caroline; Millot, Frédéric; Ricco, Jean-Baptiste; De Keizer, Joe; Pain, Stéphanie; Guétarni, Farid. (2023). Maternal, Fetal and Neonatal Outcomes Related to Recreational Cannabis Use during Pregnancy: Analysis of a Real-World Clinical Data Warehouse between 2010 and 2019.. International journal of environmental research and public health, 20(17). https://doi.org/10.3390/ijerph20176686

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