Taking antidepressants during pregnancy substantially increases the likelihood that a child will have autism, a new study suggests.

Researchers found that the odds a child would develop autism were 87 percent higher when expectant mothers took antidepressants during the last six months of pregnancy.

The findings published Monday in the journal JAMA Pediatrics come from a study looking at records on more than 145,000 Canadian children from the time of conception until age 10.

Using data about the kids and their mothers, researchers said that they factored for various circumstances including possible genetic predisposition to autism, maternal age and socioeconomic factors in order to look most specifically at the impact of medication.

“The variety of causes of autism remain unclear, but studies have shown that both genetics and environment can play a role,” said Anick Bérard of the University of Montreal, an author of the paper. “Our study has established that taking antidepressants during the second or third trimester of pregnancy almost doubles the risk that the child will be diagnosed with autism by age 7, especially if the mother takes selective serotonin reuptake inhibitors, often known by its acronym SSRIs.”

Researchers said their findings are particularly important since depression is common and an estimated 6 to 10 percent of pregnant women are taking drugs to treat the condition.

However, in an accompanying editorial, Bryan H. King of Seattle Children’s Hospital cautioned that the findings are not as clear as they may seem, especially since it’s difficult to fully determine whether the increased autism risk stems from antidepressants or the presence of depression itself.

“It makes no more sense to suggest that (antidepressants) should always be avoided than to say that they should never be stopped,” King wrote. “As this literature develops and our list of potential risk factors expands, it is also likely that its complexity will move us even farther from being able to make categorical statements about something being all good or all bad.”

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