How Marijuana Harms a Developing Baby’s Brain

From Scientific American.com (Nov. 7):

SAN DIEGO—Marijuana has been legalized in some capacity in 31 U.S. states, in large part due to a softening stance around the potential harms of the drug and recognition of its medical benefits. As a result, cannabis has become the most commonly used illicit drug during pregnancy.

One recent study revealed that in 2016 7 percent of pregnant women in California used marijuana, with rates as high as 22 percent among teenage mothers. In Colorado 69 percent of dispensaries recommended the drug to pregnant women to help with morning sickness.

Whereas marijuana is not a major health risk for most adults, prenatal drug exposure can be harmful to unborn babies. Previous research has shown infants exposed to cannabis in the womb are 50 percent more likely to have a lower birth weight. Now three new studies presented Tuesday at the Society for Neuroscience annual meeting here suggest prenatal cannabis exposure—at least in rodents—could have serious consequences for fetal brain development. “There’s become this relaxation—in part because [marijuana] is becoming legal in many states around the country—that it’s fine,” says Yasmin Hurd, who is director of the Addiction Institute at the Icahn School of Medicine at Mount Sinai and was not involved in the new research. But, she adds, just because a drug is not very dangerous to adults does not mean it is harmless to the developing brain.

In one study researchers at Washington State University in Pullman showed rat pups born to mothers exposed to high amounts of cannabis vapor during pregnancy had trouble with cognitive flexibility. [read more]