Women are already warned that using marijuana during pregnancy might affect their baby’s growth in the womb, but a new study published September 23rd in JAMA Psychiatry adds a further layer of concern: females who use cannabis while carrying may have a higher risk of their offspring exhibiting psychotic-like behaviors.
Researchers analyzed data from 11,489 children who were part of the Adolescent Brain Cognitive Development (ABCD) study, billed as the “largest long-term study of brain development and child health in the United States.”
The children’s cognitive and behavior patterns were evaluated at the age of around nine, with statements from the mothers indicating that 655 had been exposed to cannabis in the womb. Compared to the 10,834 children with no exposure, children whose mothers had used marijuana during pregnancy were more likely to have psychotic-like behaviors and more attention, social and sleep problems, as well as weaker cognitive abilities.
The study found that the vast majority of marijuana use (which was mostly recreational rather than medicinal) was during the first three months of pregnancy, often before the woman knew she was even pregnant. But significant damage might occur during the first trimester because it is one of the most sensitive times for the developing fetus brain.
For women who continued to use marijuana throughout pregnancy the negative effects for the child were more pronounced and remained after adjusting for various confounding variables. "Use of cannabis despite knowledge of pregnancy might represent a pre-existing and more severe form of cannabis use," the authors wrote.
As many as one in twenty pregnant women in the United States uses marijuana according to the Centers for Disease Control and Prevention. And they add that past studies have shown the use of marijuana during pregnancy is linked to low birth weight, impulsivity, hyperactivity, attention issues and other cognitive and behavioral issues in children.