US Pharm. 2016;41(1):16.

Expectant mothers who take antidepressants might be putting their child at substantially higher risk of autism spectrum disorder (ASD), especially if the drugs are used in the second and third trimesters, according to a review of 145,456 pregnancies.

The research, which followed the cases from conception to the children reaching age 10 years, was published recently in JAMA Pediatrics. “The variety of causes of autism remains unclear, but studies have shown that both genetics and environment can play a role,” explained lead researcher Anick Bérard, PhD, of the University of Montreal. “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 (SSRIs).”

Researchers used data from the Quebec Pregnancy Cohort, looking at a variety of factors, including information about the mother’s use of antidepressants and the child’s eventual diagnosis of autism. Exposure to antidepressants was defined as “the mother having had one or more prescriptions for antidepressants filled during the second or third trimester of the pregnancy. This period was chosen as the infant’s critical brain development occurs during this time,” Dr. Bérard said. “Amongst all the children in the study, we then identified which children had been diagnosed with a form of autism by looking at hospital records indicating diagnosed childhood autism, atypical autism, Asperger’s syndrome, or a pervasive developmental disorder. Finally, we looked for a statistical association between the two groups and found a very significant one: an 87% increased risk.”

During follow-up, 1,054 children (0.7%) were diagnosed with ASD, with boys outnumbering girls four-to-one. Use of SSRIs during the second and/or third trimester was significantly associated with an increased risk of ASD, with an adjusted hazard ratio of 2.17.

Antidepressants are widely used by pregnant women. In the U.S., the prevalence of antidepressant drug use during pregnancy increased from 5.7% in 1999 to 13.3% in 2003.

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