Assessing the prevalence and correlates of prenatal cannabis consumption in an urban Canadian population: a cross-sectional survey.

Background: Recreational cannabis use was legalized in Canada in October 2018. We aimed to determine the prevalence and correlates of cannabis consumption among pregnant individuals in a single Canadian city following national legalization.

Methods: Over the period May to October 2019, we distributed an anonymous cross-sectional survey to pregnant patients attending family practice, midwifery, and low-risk and high-risk obstetrics clinics in Hamilton, Ontario. Eligibility was based on English literacy and current pregnancy. The survey included questions regarding lifetime and in-pregnancy cannabis use, intent for postpartum use and patterns of use. We also collected demographic information. We calculated descriptive statistics and performed logistic regression analyses to explore the relations between cannabis consumption and demographic characteristics.

Results: Of 531 pregnant individuals approached, 478 agreed and were able to participate, for a 90% participation rate. Among these 478 respondents, 54 (11%) reported consuming cannabis at some point during the pregnancy and 20 (4%) reported currently consuming cannabis. Among the 460 respondents who intended to breastfeed, 23 (5%) planned to consume cannabis during the postpartum period. Of 20 current users, 13 (65%) reported consuming cannabis at least weekly and 19 (95%) reported nausea, sleep problems or anxiety as reasons for use. Respondents without postsecondary education had 10.0-fold (95% confidence interval [CI] 4.6-23.5) greater odds of prenatal cannabis consumption than university-educated respondents. In addition, respondents who reported that their partners used cannabis had 3.9-fold (95% CI 2.2-7.3) greater odds of prenatal cannabis consumption than those who reported that their partners did not use cannabis.

Interpretation: Lower educational attainment and partners' cannabis consumption were associated with greater odds of inpregnancy cannabis use. These results may help to inform early intervention strategies to decrease cannabis consumption during this vulnerable period of fetal and neonatal development.