Pregnant women’s cannabis use may change child’s brain structure

By Rebecca Burton • Published: September 7th, 2016
Category: Health in a Heartbeat

In the past decade, marijuana use has been decriminalized or legalized in many states. But pregnant women might want to think twice before lighting up. A study published in the journal Biological Psychiatry found that cannabis use during pregnancy can alter the structure of an unborn child’s brain, possibly causing behavior and mental health problems later in life.

During the study, researchers at Erasmus University Medical Center in the Netherlands analyzed data from 263 children between the ages of 6 and 8 years old who were followed from birth. About 35 percent of the children were exposed to marijuana in the womb, and most of them were also exposed to tobacco. Twenty percent of them were exposed to tobacco only, while the remainder were substance-free before birth. The researchers used MRI scans to capture each child’s brain structure and make critical measurements such as brain volume.

The children who were exposed to cannabis before birth had a thicker prefrontal cortex than those whose mothers used only tobacco. Researchers said that suggests cannabis has different developmental effects on an unborn child’s brain than tobacco. The prefrontal cortex plays a role in decision-making, social behavior and memory. There were no significant differences in total brain volume between the two groups.

The researchers said more study is needed to determine the role cannabis may play in structural changes to an unborn child’s brain. Still, they said, the current study and previous findings underscore an important point: Smoking tobacco or cannabis during pregnancy is something to be avoided.