Taking antidepressants during pregnancy does not increase the risk of autism in children, according to a new study by Women’s College Hospital (WCH) and Institute for Clinical Evaluative Sciences (ICES) scientists.
April 18, 2017 | Download Release
TORONTO, APRIL 18, 2017 – Taking antidepressants during pregnancy does not increase the risk of autism in children, according to a new study by Women’s College Hospital (WCH) and Institute for Clinical Evaluative Sciences (ICES) scientists.
The study, published in JAMA, found no significant difference between autism rates in children whose mothers took antidepressants and mothers who did not. The findings challenge previous studies suggesting that antidepressants could increase autism risk in children. Dr. Simone Vigod, MD, MSc, FRCPC, a scientist and staff psychiatrist at WCH and assistant professor at the University of Toronto, conducted the study with Hilary Brown, PhD, an adjunct scientist at WCH, and several collaborators.
“This study shows why careful analysis is so important for complex issues like the link between antidepressants and autism,” says Dr. Vigod, also an adjunct scientist at ICES. “Autism risk is related to many genetic and environmental factors and our research aims to better understand the associations.”
The scientists used administrative health data held at ICES, comparing the rates of autism diagnosed after age two between one group of children who were exposed to antidepressants in pregnancy, and another group who were not. The study only included women who were eligible for public drug coverage.
A total of 58 of the 2,837 babies born to mothers who took antidepressants (2.0 per cent) developed autism, while 335 of the 33,069 babies born to mothers who did not take antidepressants developed autism (1.0 per cent). However, after adjusting the statistical analysis to account for other factors that could have explained the risk for autism (other than antidepressants), such as diagnoses, procedures and drug claims, and comparing siblings who were and were not exposed to antidepressants, the autism risk between children who whose mothers took antidepressants vs. not was no longer significantly different.
Dr. Vigod says this second step in the analysis was essential to address the many potential differences between pregnant women who used antidepressants and those who did not. “Comparing these two groups is like comparing apples to oranges,” Dr. Vigod says. “Our deeper analysis created a level playing field for the two groups because it incorporated underlying factors such as the mother’s psychiatric history. The sibling analysis went even further by allowing us to compare children of the same mother.”
The findings suggest that previous studies might have been observing a relationship between an underlying factor associated with autism, and not antidepressant use during pregnancy. For example, depression and other psychiatric disorders share underlying genetic factors with autism. Dr. Vigod says the new findings could make a difficult choice for women easier. “The implication of our findings for pregnant women with depression is that taking antidepressants during their pregnancy does not increase the risk that their children will develop autism.”
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