Collaborative ECHO research led by Chaela Nutor, MA and Patricia A. Brennan, PhD of Emory University investigates the association between prenatal cannabis exposure and autism spectrum disorder (ASD). The study looked at data from 11,570 school-aged children from across the United States and found no evidence that prenatal cannabis exposure increases the likelihood of ASD, regardless of the child’s sex or gestational age at birth. This research, titled “Examining the Association Between Prenatal Cannabis Exposure and Child Autism Traits: A Multi-cohort Investigation in the Environmental influences on Child Health Outcomes (ECHO) Program,” is published in Autism Research.
This study included children and their mothers from 34 ECHO cohorts across the United States. ECHO researchers gathered data on cannabis use during pregnancy directly from mothers and from their medical records. They also collected information on ASD diagnosis, as well as caregiver-reported data on the children’s autism traits when the children were 1 to 18 years. The researchers used these data and reports to test whether prenatal cannabis use might be associated with ASD.
“With the legalization of cannabis in some areas of the United States, there has been a decrease in the perception of risk and an increase in cannabis use among pregnant women,” said Chaela Nutor. “While fetal exposure to cannabis has been linked to poorer neonatal and cognitive outcomes, relatively few studies have tested the association between prenatal cannabis exposure and autism spectrum disorder.”
The results of this study supported the findings from previous studies showing that initial unadjusted associations between prenatal cannabis exposure and ASD behaviors in school-aged children are no longer significant when controlling for other factors, such as maternal use of other substances during pregnancy.
The researchers are planning another large national study to further investigate the relationship between prenatal cannabis exposure and autism-related behaviors. Future work could examine the role of continued exposure to cannabis after mothers are aware of pregnancy, and other studies could investigate combined exposure to tobacco and cannabis and associated risk for ASD.