Researchers hope the findings counter recent trends of mothers using marijuana for pregnancy-related nausea symptoms.

Researchers in Minnesota and Iowa have found greater risks of social and emotional problems in infants whose mothers consumed marijuana during pregnancy.

Using results of a developmental screening tool for 1-year-olds, the researchers found that 9.1% of babies from marijuana users were at risk, compared to 3.6% of babies whose mothers didn't consume the drug while pregnant.

Researchers said the size of that gap was surprising, along with screening results showing that 8% of mothers tested positive during pregnancy for the presence of THC, the psychoactive component in marijuana, said Dr. Elyse Kharbanda, lead researcher of the study from the HealthPartners Institute in Bloomington, Minn. Researchers from the universities of Minnesota and Iowa co-authored the study, which was published in the Journal of Perinatology.

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