381 - Cannabis Use in a Pregnant population in a Post-Legalization Environment: A Canadian cohort study

Publication Number: 381.4248

Lesley J. Brennan, University of Alberta Faculty of Medicine and Dentistry, Edmonton, AB, Canada; Anne Hicks, University of Alberta Faculty of Medicine and Dentistry, Edmonton, AB, Canada; Alvaro R. Osornio-Vargas, University of Alberta, EDMONTON, AB, Canada; Matt Hicks, University of Alberta Faculty of Medicine and Dentistry, Edmonton, AB, Canada

Background: In October 2018, the Government of Canada legalized cannabis for recreational use. Cannabis use among Canadians has increased in the last decade but there are many unanswered questions about the potential benefits and harms. There is growing concern around fetal and infant cannabis exposures and the lack of data around pediatric neurodevelopmental and health implications.

Objective: To examine patterns of self-reported cannabis consumption in a pregnant population in a Canadian city.

Design/Methods: This prospective cohort study examines cannabis exposure in 131 pregnant women in Edmonton, Alberta. Participants were recruited via social media advertisements during 2022-2024. Participants responded to secure REDCap questionnaires delivered at 16-28 weeks of pregnancy characterizing demographics and cannabis use before and during pregnancy as part of a larger study that examined the association between self-reported cannabis use and biomarkers of cannabis use in urine and breast milk and child development (Figure 1).

Results: The mean age of participants in this study is 33.1(SD=4.1) years with the first survey completed at a mean of 23 (SD=4.9) weeks gestation. Most (75.6%) participants tried cannabis at some point in their life, with a median age of first use of 17 years and the earliest use of 11 years. Never users were less likely to be white, more likely to be married, and had a higher level of education (p < 0.05). Of those that confirmed past use, 48.5% used cannabis in the past year, with 66.7% consuming at a frequency of weekly or more. The preferred methods of consumption were smoking (41.7%) and oral consumption (39.5%) followed by vaping (14.6%). Cannabis products are typically purchased through a storefront (72.9%) or a licensed producer online (12.5%). Participants reported using cannabis for leisure and medical purposes (Figure 2). Among participants that confirmed cannabis use in the past year, 20 (15.3% of the total cohort) disclosed consumption in the past 30 days. More than half of this group (58.3%) use cannabis daily (Figure 3). Approximately 33% of women reported a potential secondhand exposure from a partner or housemate who smoked or vaped in the home.

Conclusion(s): In the post-legalization era, cannabis use and potential second-hand exposure is common among pregnant people. In next steps for this cohort: surveys will be completed at 32-34 weeks gestation, post-birth, early childhood; cannabis metabolites from urine and breastmilk will be analysed; and child development will be assessed out to 3 years of age.

Figure 1. Canadian cohort study examining the association between self-reported cannabis use and biomarkers of cannabis use in urine and breast milk and child development


Table 1. Self-reported reasons for cannabis consumption before and during pregnancy in participants that use cannabis surveyed at 16-28 weeks pregnant in a Canadian cohort
% of participants reporting cannabis consumption due to each symptom/concern

Figure 2. Frequency of cannabis use among pregnant participants at 16-28 weeks of gestation