No association between antidepressants during pregnancy and autism spectrum disorder in children

Analysis of health data from mothers on public drug coverage in Ontario challenges previous research findings

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 whose mothers took antidepressants versus 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.”

About Women’s College Hospital

For more than 100 years Women’s College Hospital (WCH) has been developing revolutionary advances in healthcare. Today, WCH is a world leader in the health of women and Canada’s leading, academic ambulatory hospital. A champion of equitable access, WCH advocates for the health of all women from diverse cultures and backgrounds and ensures their needs are reflected in the care they receive. It focuses on delivering innovative solutions that address Canada’s most pressing issues related to population health, patient experience and system costs.

The WCH Institute for Health System Solutions and Virtual Care (WIHV) is developing new, scalable models of care that deliver improved outcomes for patients and sustainable solutions for the health system as a whole.

Women’s College Research Institute (WCRI) is tackling some of the greatest health challenges of our time. Its scientists are conducting global research that advances the health of women and improves healthcare options for all, and are then translating those discoveries to provide much-needed improvements in healthcare worldwide.

For more information about how WCH and WCRI are transforming patient care, visit www.womenscollegehospital.ca and www.womensresearch.ca.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

For more information please contact:

Lindsay Jolivet
Research Communications Advisor
Women’s College Hospital
[email protected]
416-351-3732 ext. 2308

Deborah Creatura
Media Advisor, ICES
[email protected]
(o) 416-480-4780 or (c) 647-406-5996