Marijuana exposure in utero has lifelong consequences

A newborn mouse. (credit: Credit: Wikimedia Commons)

As marijuana is legalized in more states, questions about its safety and the health consequences of cannabis use are becoming mainstream. A new study published in PNAS finds that use of cannabis by pregnant women can have implications for the neural development of her child, and that some of the consequences continue into adulthood, So, like alcohol, another recreational drug that is legal in the US, marijuana is likely best avoided by pregnant women.

The most prominent active ingredient in marijuana is a compound known as THC, which interacts with the naturally occurring cannabinoid receptors in the nervous system. Cannabinoid receptors are known to play an important role in the regulation of brain development, and this paper examines the influence of a prenatal THC exposure on the maturation of pathways regulated by these receptors.

The study examined prenatal cannabis consumption in mice, with the aim of identifying the mechanisms responsible for cannabis-related changes in brain function. During the study, pregnant mice were exposed to daily injections of THC or injections of a control liquid. Then the offspring were run through a battery of behavioral tests. The animals’ brains were also examined closely using immunoflouresence and confocal microscopy. Embryonic brain tissue from some litters was also collected and checked for irregularities.