Why is the topic of pregnancy & cannabis use becoming more popular among Canadian youth?

There are a lot of opinions on the topic of cannabis use during pregnancy and breast/chest feeding , but what is the research saying? Since the legalization of cannabis in 2018, 4-11% of people have reported using cannabis at least once while pregnant and/or nursing, making it the second most used psychoactive substance after alcohol. Cannabis use by pregnant and lactating people is increasing, though it is difficult to establish the prevalence of cannabis use in pregnancy and the post-partum period.

People choose to use cannabis while pregnant or nursing for a range of reasons. Pregnant people have reported using cannabis to manage pregnancy-related conditions (e.g., nausea, weight gain, sleep difficulty) and pre-existing conditions (e.g., mental health, insomnia, chronic pain), as well as to improve mood, mental, physical and spiritual well-being, provide pleasure and manage stress.

If people report that it can help them manage symptoms, why are there concerns about cannabis use during pregnancy and lactation? Evidence shows that the exposure to certain cannabinoids (THC and CBD) can have a range of long-lasting effects on the developing baby due to the fact that cannabinoids can permeate the placenta as well as remain present in breast milk for up to 6 days. Some of the potential impacts include:

  • Preterm birth
  • Neurodevelopmental impacts
  • Cognitive, social, and motor impacts
  • Low birth weight
  • Drowsiness and disturbed sleep
  • Reduced memory function
  • Increase in hyperactive, impulsive, and aggressive behavior.

The Endocannabinoid system (ECB) is involved in regulating nausea, pain and appetite. It plays a vital role in pregnancy, specifically the maintenance of the implantation, the growth of the placenta, and prenatal development. THC (the main psychoactive ingredient resulting in the “high”) is linked with the majority of the effects people associate with cannabis. Since THC interacts with disrupts the ECB, it may have lingering and prolonging effects on prenatal development.

In 2019, a Canadian study investigated whether pregnant people would be advised to use cannabis during pregnancy for symptoms such as nausea and anxiety. Ot found that 93% of dispensaries in Canada advised against the use – a vast difference from the initial study done in Colorado where 70% recommended use in the first trimester.

So how can pregnant and lactating people reduce potential harms?

  • Use cannabis products containing less THC
  • Consume cannabis less often (1x week)
  • Refrain from smoking cannabis (edibles are shown to have a softer effect)
  • Only use cannabis from regulated dispensaries
  • Avoid mixing cannabis with other substances (tobacco, alcohol, other medications)

There are also many alternatives for treating nausea during pregnancy:

  • Stay hydrated
  • Eat small meals and snacks throughout the day
  • Consume salty foods such as crackers or chips
  • Drink or eat ginger based products to aid in digestion
  • Use Dimenhydrinate (Gravol) to decrease nausea symptoms
  • Sleep and nap throughout the day

Written By:

Aislin McWilliam

Research by

Alsa St Rose

Redait Kasahwni

Shanice Nyawira Tya Thompson

Check out our Ask The Expert session on Navigating Cannabis During Pregnancy & Chest/Breastfeeding.

Link: https://youtu.be/o1MUKiyf4TA



Other research

Davis, Lee, T., Weber, J. T., & Bugden, S. (2020). Cannabis use in pregnancy and breastfeeding: The pharmacist’s role. Canadian Pharmacists Journal / Revue Des Pharmaciens Du Canada, 153(2), 95–100.

Moss, M. J., Bushlin, I., Kazmierczak, S., Koop, D., Hendrickson, R. G., Zuckerman, K. E., & Grigsby, T. M. (2021). Cannabis use and measurement of cannabinoids in plasma and breast milk of breastfeeding mothers. Pediatric research, 90(4), 861-868.

NIDA. 2019, August 9. Is Cannabis (Marijuana) Safe to Use While Pregnant or Breastfeeding?. Retrieved from

https://nida.nih.gov/publications/cannabis-safe-to-use-while-pregnant-or-breastfeeding on 2023, September 8