With areas of expertise in cannabis use and brain disorders, Justine Renard from the Canadian Centre on Substance Use and Addiction spoke to Lorna Rothery about the prevalence and potential impacts of cannabis use during pregnancy
How common is cannabis use during pregnancy in Canada?
Cannabis use among pregnant individuals in Canada is estimated at 4-5%, but accurate data is hard to obtain due to under-reporting and associated stigma. Some recent research from Ontario shows an increase in usage from about 1% in 2012 to roughly 4.3% in 2022, particularly among younger individuals. Other studies show that since cannabis legalization in 2018, the rate of acute care (i.e. emergency department visits or admission to hospital) related to its use during pregnancy has nearly doubled, rising from 11 to 20 per 100,000 pregnancies, predominantly affecting those under 35, people living in rural areas, and individuals with lower incomes or mental health issues.
Significantly, increased acute care visits have been associated with a higher incidence of adverse neonatal outcomes. Although the estimate of cannabis use during pregnancy is 4-5%, the rise in acute care visits may indicate that more people than thought are using cannabis; however, due to stigma or the fear of being judged for using cannabis during pregnancy, this increase is likely underreported.
What are some reasons for cannabis use during pregnancy?
There are various reasons why someone might use cannabis during pregnancy; some individuals may be new users, while others may have been using it before pregnancy and continued to do so. People using cannabis during pregnancy may believe it helps alleviate nausea, vomiting, and pain associated with pregnancy. For individuals experiencing strong morning sickness, cannabis might seem like a potential relief. Others may turn to it for stress and anxiety reduction because of its relaxing effects. Additionally, since cannabis is a plant-based product, some may assume it is safer than pharmaceuticals.
In Canada, changes in legalization have also influenced attitudes toward cannabis. The perception of cannabis as a harmful substance has shifted over time, leading some to believe it might be safe to use during pregnancy. There is still insufficient research to confirm its effectiveness or safety in this context.
Do we know how much and what kinds of cannabis products pregnant people are using?
Research does not consistently track the exact dose, frequency, or specific products used by pregnant individuals. This variability can complicate efforts to assess the exact risks associated with different forms and amounts of cannabis use during pregnancy. It’s also important to note that cannabis products available today often contain higher levels of THC (tetrahydrocannabinol), the psychoactive component of cannabis. Over the last decade, THC concentrations in many products have increased considerably.
Additionally, the methods of consumption can vary; some individuals may choose to smoke, vape, or use edibles or oils, each of which can have different effects. These variations further complicate research efforts to evaluate the specific risks associated with other forms of cannabis use during pregnancy.
What does research tell us about the potential impact on fetal development and long-term influences on cognition, behaviour, and mental health?
There is growing evidence suggesting that cannabis use during pregnancy may have significant implications for fetal development and long-term health outcomes. The main concern is THC can cross the placenta and potentially affect fetal brain development. The fetus undergoes crucial developments during the prenatal stage, especially in the brain. The ability of THC to enter the fetal brain can have adverse effects.
Research indicates that frequent cannabis use during pregnancy is linked to lower birth weight and preterm birth. Furthermore, some other studies have shown long-term effects on a child’s behaviour and cognition, including difficulties with attention, hyperactivity, impulsivity, and emotional challenges. Some research also suggests a connection between prenatal cannabis exposure and sleep disturbances in children, as well as a possible increased likelihood of substance use later in life. There are also studies implying links between prenatal cannabis exposure and congenital abnormalities, including autism.
While more research is needed to confirm these findings, the existing associations are concerning. Given the potential risks, it is recommended that pregnant individuals avoid cannabis use. If abstinence is not possible, minimizing use and avoiding high-THC products may help reduce potential harm.
What are the challenges of assessing the impact of prenatal cannabis exposure?
Studying the effects of cannabis presents numerous challenges due to the complexity of the process, which can take years or even decades to understand fully. Longitudinal research is often required, tracking development over time, and sometimes even before birth, to evaluate the prenatal impact of cannabis use. This type of research demands consistent follow-up, which can be costly and time-consuming for researchers and participants. Additionally, many participants may drop out over time, resulting in incomplete data that complicates the ability to draw solid conclusions.
There are also confounding factors that hinder researchers’ efforts to isolate the effects of cannabis from other influences. Child development can be affected by various factors, including genetics, socioeconomic background, nutrition, and exposure to other substances. This makes it difficult to determine whether cannabis alone is responsible for observed outcomes or if they result from a combination of different factors and influences.
Moreover, many researchers rely on retrospective data, asking participants to recall past behaviours, such as cannabis use during pregnancy. This can introduce recall bias, as memory is not always accurate; participants may forget, misjudge, or underestimate their cannabis use. The stigma surrounding substance use during pregnancy can further lead individuals to downplay or avoid reporting their cannabis use in studies.
Additionally, the cannabis products themselves have changed over time. The potency of cannabis has changed over the years. Consequently, findings from studies conducted ten or 20 years ago may not accurately reflect current cannabis exposure risks. The various methods of cannabis consumption – such as smoking, vaping, and edibles – add another layer of complexity to the research.
What are the challenges for health professionals when addressing cannabis use during pregnancy?
Discussing cannabis use presents challenges for healthcare professionals, including doctors and midwives, mainly due to a lack of conclusive research. This makes it difficult for them to offer definitive recommendations, leading to inconsistent messaging. Additionally, patients often fear judgment or legal repercussions, which can discourage them from disclosing their cannabis use, further complicating providers’ ability to give appropriate guidance.
The CCSA will try to understand healthcare professionals’ comfort levels in discussing cannabis use with patients and to develop resources that support these conversations. It’s crucial for healthcare providers to prioritize open, non-judgmental dialogue, enabling patients to make safe choices.
Instead of outright rejecting cannabis use, healthcare professionals can suggest alternatives, such as lower THC options or other medications for symptoms like nausea. While avoiding cannabis during pregnancy is ideal, users need to understand potential risks.
Pregnancy and cannabis use is a very important topic of interest for the CCSA, and we will pursue our research efforts on this topic. For example, we will be conducting a research project to explore perceptions and behaviours surrounding cannabis use among pregnant individuals. We aim to provide clear, evidence-based guidance, ensuring individuals have the best information to make informed decisions for themselves and their developing babies. We strive to better understand why they use cannabis, their patterns of use, and their choices regarding consumption. This understanding will help us create targeted information about cannabis use and minimize the risks associated with its use during pregnancy.
