Endocannabinoid Signaling in Early Neurodevelopment: Effect of Gestational Δ9-THC Exposure

Marijuana is the most commonly abused illicit drug by pregnant women in the world. Its psychoactive cannabinoid, 9 -tetrahydrocannabinol, crosses the placenta and accumulates in the fetus, potentially harming its development. In humans, marijuana use in early pregnancy is associated with an increased risk for miscarriage, anencephaly, as well as subtle neurodevelopmental defects in the offspring, including ADHD, psychiatric disorders, learning disabilities and memory impairment. Little is known about the mechanisms by which marijuana exert its detrimental effects on the developing embryo, although recent evidence points to the possibility that 9 tetrahydrocannabinol might interfere with an endogenous endocannabinoid system present in the embryo during early stages of pregnancy. Here we review our current knowledge on evidence for an endocannabinoid system in early embryonic development and discuss a possible mechanism of action for 9 -tetrahydrocannabinol in early pregnancy.