Is cannabis-use during pregnancy safe? Despite the growing number of pregnant women using cannabis, Public Health officials warn against it.

By: Caine Meyers

A year after legalization, cannabis is ubiquitous in Canada. Today, there is a reported growing number of women using the drug during pregnancy to alleviate morning sickness. According to a recent study published in the Canadian Journal of Public Health, the trend is expected to continue.¹ They found that approximately 1.2% of women in Ontario smoked cannabis during pregnancy in 2012. This number increased to 1.8% in 2017. Most of these women were between the ages of 15-24 years.

Earlier this year, Dr. Mark Walker, head of obstetrics at the Ottawa Hospital and co-author of the Ontarian study, warned Global News that there are no safe amounts of cannabis exposure during pregnancy.² In fact, he cautioned that the safest option for an unborn child is no cannabis use at all, given the lack of clinical evidence determining the benefits or risks of cannabis-use during pregnancy.

A recent presentation at the annual Experimental Biology conference in Orlando, Florida highlighted new evidence on the effects of prenatal cannabis exposure.³ Researchers reported that cannabis affects a baby’s brain’s learning and memory centre, the hippocampus, by altering specialized and complex neuronal connections. In other words, pre-natal cannabis exposure reduces a specialized protein in the hippocampus called neural cell adhesion molecules (NCAM). NCAM promotes strong, healthy connections between neurons.

Author of this publication, Priyanka Pinky, warned reporters of Experimental Biology, “Based on our research and the previous existing findings in the field, it can be said that using marijuana during pregnancy would not be a wise choice. However, it is also notable that the observed effect in the off-spring can vary according to their age and according to the trimester in which they were exposed to the drug, as well as dose and route of administration of the drug.”⁴ This warning is merited. Research indicates that a third of women who smoke marijuana will continue to do so once pregnant.⁵ Reportedly, 75% of women who do discontinue cannabis-use during pregnancy do so to avoid setting a bad example. Only 27% quit as per their physician’s recommendation.⁵ This points to the lack of understanding and knowledge of potential serious and adverse effects.

Pinky’s study adds to the previous body of literature examining the effects of pre-natal exposure to marijuana. A study published in 2017 found that infants exposed to cannabis during pregnancy were smaller in length, weight, and head size, and more likely to be born premature.⁶ Later-on, these children were reported to be more irritable and easily frustrated. In addition, another study found that these effects persist and have an effect on a child’s behaviour until at least the age of 10.⁷ It is important to caution that some participants in these studies reported conjunctive tobacco use. In fact, it is likely that concurrent use of tobacco and cannabis during pregnancy confounds these effects.

Ultimately, the exact effects of cannabis during pregnancy are still under investigation. Because of this, it is heavily cautioned that pregnant women think twice before taking the drug. Indeed, it does appear that cannabis does affect the pre-natal brain. However, until further, long-term research is published, long-term consequences are unknown. If you believe that you or a loved one is struggling with cannabis dependency or addiction, please feel free to reach out. Sobriety Home is a state-of-the-art addictions treatment facility with highly trained counsellors and medical professionals on site.

References

1. Corsi DJ, Hsu H, Weiss D, Fell DB, Walker M. Trends and correlates of cannabis use in pregnancy: a population-based study in Ontario, Canada from 2012 to 2017. Can J Public Health. 2019;110(1):76-84. doi:10.17269/s41997-018-0148-0

2. More Ontario women using cannabis while pregnant despite warnings | Globalnews.ca. https://globalnews.ca/news/4916337/cannabis-pregnancy-ontario-women/. Published February 1, 2019.

3. Pinky P, Bloemer J, Dityatev A, et al. Mechanism of Prenatal Cannabinoid Exposure Mediated Memory Loss in Adolescent Offspring: Opportunities for Identifying Therapeutic Target. FASEB J. 2019.

4. Marijuana for morning sickness? It’s not great for baby’s brain. EurekAlert! https://www.eurekalert.org/pub_releases/2019-04/eb-mfm032819.php.

5. Mark K, Gryczynski J, Axenfeld E, Schwartz RP, Terplan M. Pregnant Women’s Current and Intended Cannabis Use in Relation to Their Views Toward Legalization and Knowledge of Potential Harm. J Addict Med. 2017;11(3):211-216. doi:10.1097/ADM.0000000000000299

6. Prenatal Risk and Infant Regulation: Indirect Pathways via Fetal Growth and Maternal Prenatal Stress and Anger – Schuetze – 2018 – Child Development – Wiley Online Library. https://onlinelibrary.wiley.com/doi/full/10.1111/cdev.12801.

7. Goldschmidt L, Day NL, Richardson GA. Effects of prenatal marijuana exposure on child behavior problems at age 10. Neurotoxicol Teratol. 2000;22(3):325-336.