A study by The Ottawa Hospital suggests that children born to mothers who used cannabis while pregnant are more likely to have autism, CTV reports. The study, believed to be the largest of its kind, reviewed more than 500,000 births in Ontario, Canada from April 2007 to March 2012.
While the research does not prove that cannabis use during pregnancy causes autism, it purports an association between the two factors. The study also does not indicate how much cannabis, the type, or the strength, consumed by the expectant mothers or how often they consumed cannabis or at what stage of pregnancy.
According to a study published in Nature, 0.6 percent of the mothers of those children reported using cannabis during pregnancy. The researchers found that 1.4 percent of the children whose records they examined were diagnosed with autism spectrum disorder and that figure increased to 2.2 percent if their mother had reported cannabis use during pregnancy – a risk that was present even if cannabis was the only substance the mother reported using. Cannabis was still illegal in Canada during the timeframe used by researchers.
Health Canada guidelines say there “is no safe amount of cannabis use during pregnancy.”
Study author Dr. Darine El-Chaâr, a maternal-fetal medicine specialist and clinical investigator at Ottawa Hospital Research Institute, said that she was “not too surprised” by the findings.
“Women who used cannabis during pregnancy were 1.5 times more likely to have a child with autism. These are not reassuring findings. We highly discourage use of cannabis during pregnancy and breastfeeding.” – El-Chaâr in a statement to CNN
El-Chaâr noted that expectant mothers often say they use cannabis during pregnancy for pain management, or nausea or vomiting; however, some use it recreationally as “part of their routine.”
The American College of Obstetricians and Gynecologists says there is “insufficient data to evaluate the effects of marijuana use on infants during lactation and breastfeeding” and discourages cannabis use “in the absence of such data.” The organization recommends pregnant women discontinue medical cannabis use in favor of pregnancy-safe alternatives.