The research on the health effects of cannabis is growing rapidly, as summarized in a review by Roncero et al 2020 [1]. Studies on babies and children whose mothers used cannabis while pregnant show that a number of health effects may be related. Babies exposed to cannabis prenatally are more likely to have grown less in utero, have a lower birth weight, and a smaller head circumference. Studies have shown that the parts of these babies' brains involved in emotional processing may be affected, and that they may sleep fewer hours, have more aggressive behavior, and be less able to pay attention. Prenatal cannabis exposure may also affect different parts of the immune system and cause babies to have a lower immune response to viruses. It may also cause ventricular septal defects, or a hole in part of the heart that may require surgery to fix.

 

Children and adolescents whose mothers used cannabis while pregnant are more likely to have a lower IQ, less ability to pay attention, altered short-term memory, greater impulsiveness, and reduced abstract and visual-spatial reasoning. They also are at greater risk for delinquent behavior, use of cannabis and nicotine, and Tourette's syndrome.