Significant risks of exposure to cannabis during pregnancy discovered in new research


A new study by researchers from Western University and Queen’s University definitely shows that regular exposure to THC, the main psychoactive ingredient in cannabis, during pregnancy has a significant impact on placental and fetal development. With more than a year since the legalization of recreational cannabis in Canada, the effects of its use during pregnancy are only beginning to be understood.

The study, published today (January 17, 2020) in Scientific reportsIt uses a model of rat and human placental cells to show that maternal exposure to THC during pregnancy has a measurable impact on both the development of the fetus’s organs and on gene expression that is essential for placental function.

Researchers demonstrated in a rat model that regular exposure to a low dose of THC that mimics daily cannabis use during pregnancy led to an 8 percent reduction in birth weight and decreased brain and liver growth in more than 20 percent.

“These data support clinical studies that suggest that cannabis use during pregnancy is associated with low birth weight babies. The clinical data is complicated because they are confused by other factors such as socioeconomic status, “said Dan Hardy, PhD, associate professor at the Western Schulich School of Medicine and Dentistry and co-author of the article.” This is the first study that definitely supports the fact that THC only has a direct impact on placental and fetal growth. “

In a rat model, regular exposure to a low dose of THC that mimics daily cannabis use during pregnancy led to an 8 percent reduction in birth weight and decreased brain and liver growth by more than 20 percent.

The research team was also able to characterize how THC prevents oxygen and nutrients from crossing the placenta into the developing fetus. By studying human placental cells, researchers discovered that exposure to THC caused a decrease in a glucose transporter called GLUT-1. This indicates that THC prevents the placental transfer of glucose, a key nutrient, from the mother to the fetus. They also found a reduction in placental vasculature in the rat model, which suggests reduced blood flow from the mother to the fetus.

The researchers say both factors probably contribute to the growth restriction they observed in the offspring.

The researchers point out that there are currently no clear guidelines from Health Canada on the use of cannabis in pregnancy and some studies have shown that up to one in five women use cannabis during pregnancy to prevent morning sickness, anxiety or for social reasons.

Dan hardy

Dan Hardy, PhD, Associate Professor, Schulich Medicine & Dentistry, Western Unversity. Credit: Western University

“Marjiuana has been legalized in Canada and in many US states. UU., However, its use during pregnancy has not been well studied until now. This study is important to help doctors communicate the very real risks associated with cannabis use during pregnancy, “said David Natale, PhD, Queen’s associate professor and co-author of the article.

Reference: “Exposure to Δ9-tetrahydrocannabinol during pregnancy in rats leads to symmetric restriction of fetal growth and specific vascular defects of the labyrinth in the placenta” by Bryony V. Natale, Katarina N. Gustin, Kendrick Lee, Alison C. Holloway , Steven R. Laviolette, David RC Natale and Daniel B. Hardy, January 17, 2020, Scientific reports.
DOI: 10.1038 / s41598-019-57318-6


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