A new study suggests that kids whose moms used cannabis after the fifth or sixth week of pregnancy may be more likely to develop mental health issues in early adolescence.
According to a report published in JAMA Pediatrics, an analysis of data from more than 10,000 kids aged 11 and 12 revealed that exposure to cannabis in utero was associated with a higher risk of developing disorders such as aggressive behavior, ADHD, rule-breaking behavior, and conduct disorder.
David Baranger, the study's first author and a postdoctoral research associate at Washington University in St. Louis, said that the take-home message from this study is that there is some evidence that one should be cautious about using cannabis during pregnancy.
Results fall in line with earlier research on the same children
Baranger added that the new study is an association and can't prove that cannabis is the cause of mental health problems. The results, however, align with earlier research on the same kids, who were also participants in the ongoing Adolescent Brain Cognitive Development (ABCD) study.
The long-term project has been tracking the brain development of nearly 12,000 kids via MRI scans. This study is supported by the National Institutes of Health (NIH). Baranger said that the children's brain scans showed a hint of a potential impact of cannabis.
A study conducted in 2019 that looked at the kids when they were 9 and 10 found the same association between behavioral issues and prenatal cannabis. The study also showed that children exposed to cannabis in utero tended to have lower brain volume, white matter volume, and birth weight.
The number of women using cannabis during pregnancy in the United States is growing. According to a government survey, 4.7 percent of pregnant women reported cannabis use in 2018 and 5.4 percent in 2019.
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Impact of cannabis use seen in the middle of first trimester
Baranger advised pregnant women who rely on marijuana to help with their nausea to talk to their health care provider. Baranger and his colleagues analyzed data from 10,631 kids participating in the brain study by the NIH.
The researchers compared three groups of children in the study: those whose moms did not use cannabis during pregnancy, those whose moms were using cannabis but quit when they learned they were pregnant, and those whose moms continued to use cannabis after learning they were pregnant.
According to the study, the impact of cannabis use was seen in the middle of the first trimester. Baranger told NBC News that the use of cannabis earlier in the pregnancy before the mothers discovered they were pregnant, did not appear to have an impact on the risk of the kids developing behavior issues. Baranger suspects that is because cannabinoid receptors have not yet developed in fetal brains.