Exposure to THC during pregnancy affects fetal development, new study shows

Regular cannabis use during pregnancy has a significant impact on placental and fetal development, according to a new study conducted by researchers at Western University and Queen's University.

The study, published in the journal Scientific Reports, found regular exposure to low doses of THC during pregnancy led to a reduction in birth weight by eight per cent, and decreased brain and liver growth by more than 20 per cent. 

"This is the first study to definitively support the fact that THC alone has a direct impact on placental and fetal growth," said Dan Hardy, a Western associate professor and co-author of the study.

THC is the main psychoactive ingredient found in cannabis. 

Researchers used a rat model and human placental cells, and applied small doses of THC that would mimic daily use of cannabis during pregnancy.

They noted THC prevented oxygen and nutrients from crossing the placenta into the developing fetus. 

In particular, THC decreased the levels of GLUT-1, a transporter responsible for sending glucose from the mother to the fetus. 

"This data supports clinical studies that suggest cannabis use during pregnancy is associated with low birth weight babies. Clinical data is complicated because it is confounded by other factors such as socioeconomic status," Hardy said.