Is Marijuana Good for Your Pregnancy? New Study Shows Abnormal Brain Structure in Exposed Children

A new study shows that the use of marijuana during pregnancy is related to abnormal brain structure in children. Comparing children prenatally exposed to marijuana with the unexposed ones, the former showed thicker prenatal cortex, a part of the brain that is involved in decision-making, working memory and complex cognition.

In a study released in the Biological Psychiatry, children prenatally exposed to marijuana have thicker prenatal cortex than those who were not exposed. The study, led by Dr. Hanan El Marroun of the Erasmus University Medical Center in the Netherlands, sprang from the issue of the rising cases of marijuana use during pregnancy in the country and the absence of thorough studies on its effects on the fetus and in the child's developing years.

According to the researchers, an estimated 2-13% of women use marijuana during pregnancy. While there have been previous studies that showed short and long-term effects of prenatal cannabis exposure on the children's behavior, there had not been enough studies on the effects on the brain morphology of the exposed child. Understanding how the exposure affects the child's brain could also lead to understanding how the child "develops after being exposed to marijuana", said El Marroun.

El Marroun and her team used structural magnetic resonance imaging to study the brains of 54 children, aged between six to eight, all of whom were prenatally exposed to marijuana. Some of them (those who were prenatally exposed to not just marijuana but tobacco as well) were also compared to 96 children who were prenatally exposed to tobacco only, and to 113 children who were not exposed to either. The study, conducted in the Netherlands, was of a prospective population-based nature.

The results of the tests between the joint marijuana and tobacco prenatally exposed children to that of tobacco-only and marijuana-only respondents showed that the ones exposed to tobacco had cortical thickness differences. Meanwhile, the marijuana-only prenatally exposed children did not have any differences in overall brain volume.

The team is cautious on the interpretation of the results, though, and says that this is still a work in progress, and further studies on the long-term effects of prenatal exposure to marijuana should be conducted.