Women are increasingly using marijuana during pregnancy, especially as more states in the United States and other countries legalize its use. The trend has raised questions about how the substance affects fetal development.
Of the half-million registered children, 7,125 were diagnosed with autism, the team found. And, [researcher Daniel] Corsi says, the prevalence of autism was higher among children born to women who had used marijuana during pregnancy.
There are other confounding factors that the retrospective data can’t capture, Corsi and others say.
For example, the information on a mother’s psychiatric condition only captures her diagnosis, and does not take into account undiagnosed conditions or those in the father or other family members. Also, the socioeconomic status may be skewed because researchers measured it using census data on the area where the mothers lived, rather than individual household income.
And the data on marijuana use indicates only whether a mother used marijuana at all, not how much or often or whether for recreational or medicinal purposes — to treat nausea, for example.
“It’s a great use of the data that was there, but I would like to see that kind of evidence in the future to help us really assess if this is a true association,” [Keely] Cheslack-Postava says. As it stands, the study shows that the relationship between marijuana and autism is “a question that deserves further examination.”