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Cannabis Use During Pregnancy Linked With Abnormal Brain Structure in Kids

The first study to look at pot’s effects on brain morphology.

| 2 min read

The first study to look at pot’s effects on brain morphology.

According to a new study, marijuana use during pregnancy may affect brain development in offspring, leading to an abnormal brain structure.

"This study is important because cannabis use during pregnancy is relatively common and we know very little about the potential consequences of cannabis exposure during pregnancy and brain development later in life,” study author Dr. Hanan El Marroun, of Erasmus University Medical Center in The Netherlands, said in a press statement.

Compared the children who weren’t prenatally exposed to cannabis, the pot-exposed children had a thicker prefrontal cortex, which is a brain region involved in decision-making, working memory, and complex cognition.

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To come to this conclusion, the researchers recruited 263 children aged 6 to 8 for the study — 54 who had been prenatally exposed to marijuana, 96 exposed to tobacco, and 113 control children with no exposure. The children were part of the Generation R Study, a population-based study in the Netherlands.

The tobacco group was investigated since the researchers found that most of the children exposed to cannabis were also exposed to tobacco, so they needed to distinguish the differences between the effects of the two substances.

Using MRI scans, the researchers assessed brain volumetric measures and cortical thickness.

The results, which have been published in the journal Biological Psychiatry, show that prenatal cannabis exposure wasn’t associated with global brain volumes, like gray matter or white matter volume. However, marijuana exposure was linked to thicker frontal cortices compared to the non-exposed or tobacco-exposed children, suggesting that cannabis has different effects on brain development than tobacco.

"The growing legalization, decriminalization, and medical prescription of cannabis increases the potential risk of prenatal exposure," said Dr. John Krystal, editor of Biological Psychiatry. "This important study suggests that prenatal exposure to cannabis could have important effects on brain development."

However, El Marroun points out that the results of the current study should be interpreted with caution. Although a link was found between prenatal cannabis exposure and abnormal brain structure, further research is needed to confirm the causal nature of this relationship.

"Nevertheless, the current study combined with existing literature does support the importance of preventing smoking cannabis and cigarettes during pregnancy," she concluded.

Read next: Long-Term Study Links Marijuana Use to Gum Disease

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