Moms-to-be, take note! Smoking cannabis during pregnancy may cause abnormal brain structure in babies, affecting regions linked to complex cognition, decision-making and working memory, a new study has warned.
An estimated 2-13 per cent of women worldwide use cannabis during pregnancy, researchers said.
Previous studies have identified short and long-term behavioural consequences of prenatal cannabis exposure, but effects on brain morphology were unknown.
Compared with unexposed children, those who were prenatally exposed to cannabis had a thicker prefrontal cortex, a region of the brain involved in complex cognition, decision-making, and working memory.
“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,” said Hanan
El Marroun, from the Erasmus University Medical Centre in The Netherlands.
“Understanding what happens in the brain may give us insights in how children develop after being exposed to cannabis,” said El Marroun.
Researchers used structural magnetic resonance imaging (MRI) to examine the brains of 54 children, 6 to 8 years old, who were prenatally exposed to cannabis.
Most of the children exposed to cannabis were also exposed to tobacco, so the researchers compared them to 96 children prenatally exposed to tobacco only, as well as to 113 control children with no exposure.
The children were part of a prospective population-based study in The Netherlands.
Comparing tobacco-exposed children with those exposed to both tobacco and cannabis showed differences in the cortical thickness, suggesting that cannabis exposure has different effects than tobacco.
No differences were found in overall brain volume in the cannabis-exposed children, researchers said.
“We have to be careful interpreting the results of the current study,” said El Marroun.
The study was published in the journal Biological Psychiatry.