Walker OS, Holloway AC, Raha S. The role of the endocannabinoid system in female reproductive tissues. J Ovarian Res 2019;12:3 (article)

Martinez-Pena AA, Perono GA, Gritis SA, Sharma R, Selvakumar S, Walker OS, Gurm H, Holloway AC. The impact of early life exposure to cannabis: the role of the endocannabinoid system. Int J Molecular Sci 2021;22:8576 (article)

Why was this study conducted?

There is growing concern about the effects of cannabis use during pregnancy and/or lactation but to date compelling evidence to guide clinicians and healthcare policy has been limited. Both articles are non-systematic reviews of our current state of knowledge on two related topics: 1) the role and functioning of the endocannabinoid system in female reproductive tissue; and 2) the effects of prenatal exposure to cannabinoids (both endogenous and exogenous) on the placenta, and thus the developing fetus. There is some overlap in the authorship of the articles, as both reviews were conducted by researchers at McMaster University.


What does this study add?

The reviews summarize what is known from in vitro, in vivo, pre-clinical and clinical studies about the effect of endocannabinoids, and by extension phytocannabidinoids, on female reproductive functioning and health. The Walker et al. review looks at the evidence that by interfering with some hormones, cannabis negatively impacts ovarian functioning (including the progression of polycystic ovarian syndrome or PCOS). These changes may, in some cases, have beneficial effects, e.g., disturbing the signaling pathways involved in tumour progression. The Martiniez-Pena et al review focuses on what is known about the role of cannabinoids (both endocannabinoids and from the use of cannabis during pregnancy) on placental functioning.

Is there anything else I should know?

Both articles note that there is much to learn about the reproductive effects of endocannabinoids and thus the implications of cannabis use during pregnancy. Due to research constraints, much of the evidence is drawn from pre-clinical (e.g., animal or cellular) studies and have tended to focus on only a few cannabinoids, such as ∆-9-tetrahydrocannabinol (THC). The articles were not designed for clinicians working directly with patients but contain background information that could be useful in interpreting clinical guidelines.

Author Details

The latest scientific evidence on this topic was reviewed by the Centre's leadership team. This research summary is written by Corinne Hodgson, DHealth, assessed for accuracy by Dr. James MacKillop, PhD. There are no conflicts of interest. Questions regarding this piece should be directed to Dr. James MacKillop (jmackill@mcmaster.ca).

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