Antidepressants during pregnancy raises autism risk

A new study shows an increased risk of a child developing autism if the mother takes antidepressants during pregnancy.

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Using antidepressants in the second and third trimesters of pregnancy nearly doubles the risk the child will develop autism, according to a new study from researchers at the University of Montreal, published today in JAMA Pediatrics. And the risk was even greater for babies exposed to the most popular form of antidepressants used in pregnancy—selective serotonin reuptake inhibitors, or SSRIs.

Researchers examined data for 145,456 full-term pregnancies in Quebec between 1998 and 2009, and found the rate of autism spectrum disorders was 0.7 percent in kids not exposed to antidepressants. But the autism rates jumped to 1.2 percent for babies exposed to any antidepressant during the second and/or third trimester, and to 1.4 percent among babies exposed to only an SSRI during the second or third trimester. The study showed no increased risk of developing autism when antidepressants were only used in the first trimester.

Statistically, when adjusted for other factors, this represents an 87 percent increased risk of developing autism for babies exposed to antidepressants during the second and/or third trimesters, and a 117 percent increased risk for babies exposed to SSRIs during this period. It sounds alarming, but consider the hard numbers: 31 out of 2,532 children exposed to antidepressants after the first trimester were diagnosed with autism.

Still, the study’s lead author, Anick Bérard, says the numbers are significant. “Any increase in risk is too high,” says Bérard, an expert on medication and pregnancy and a professor in the Faculty of Pharmacy at the University of Montreal. “Depression is very debilitating and should be treated. But there is a societal belief that depression absolutely needs to be treated with antidepressants. We need to treat it differently, at least during pregnancy,” she said.

If Bérard is right, her warning applies to tens of thousands of pregnant women in Canada alone. According to the Public Health Agency of Canada, 10 percent of all pregnant women struggle with depression during pregnancy.

Untreated depression during pregnancy has been linked to a host of developmental problems in babies and children, from low birth weight and pre-term birth to hyperactivity in older children. It has also been tied to elevated risks for postpartum depression among mothers, which can impact maternal bonding, attachment, and if left untreated can lead to chronic maternal depression. But no study has definitively proven that antidepressants are safe for use during pregnancy. This has made decisions around how to treat depression in expectant women murky. For many, Bérard’s findings will muddy the water even further.


“I would hate for this to be used to scare women away from antidepressants,” said Simone Vigod, a psychiatrist and researcher at Women’s College Hospital in Toronto. A specialist in maternal mental illness, Vigod was not involved in this study, although she reviewed it for Today’s Parent.

While Vigod believes “antidepressants are not a panacea,” she and other clinicians who favour prescribing medication to women diagnosed with depression during pregnancy do so because it tends to produce fast results, she said. Two-thirds of first-time sufferers respond to antidepressants in less than three weeks, compared with the three months it typically takes for alternative therapies, such as non-medicated psychotherapy, to effect change. “That’s leaving a fetus exposed to depression during that time,” she said. And when it comes to private talk or group therapy, many have trouble getting access and paying for it.

For patients who are already taking antidepressants when they become pregnant, Vigod said clinicians approach the issue on a case-by-case basis with an eye to balancing a mother’s mental health with the overall health of her unborn baby. In many cases, that means sticking with an antidepressant regime to avoid a relapse back into depression. The likelihood of a relapse, she said, depends on the severity of a person’s depression and the number of past episodes suffered. Studies show those who have suffered multiple, moderate to severe episodes of depression are the most likely to relapse if they abandon medication when they become pregnant. No mother she has treated takes the decision lightly, Vigod says.

“You’re probably not going to take an antidepressant unless you’re of a severity that makes you feel you’re at your tipping point,” she said. “A lot of women don’t care about themselves or their own depression—they can’t get away from what might happen to the baby. In fact, it’s the kids of untreated moms who have more mental health and development issues.”

Vigod urged caution when interpreting the results of Bérard’s research. She says the increased risk of autism spectrum disorder it indicates is too small to warrant widespread change.


As noted, the research found an 87 percent increased risk of a child having autism if the mother took some kind of antidepressant during the second and/or third trimester of pregnancy, and a 117 percent increased risk if the mother took an SSRI during that period. What does that translate to?

Say you have a group of 1,000 babies who weren’t exposed to antidepressants during the pregnancy—based on the data in this study, seven would later be diagnosed with autism by age seven. Now if we were to compare this to a group of 1,000 babies who were all exposed to an antidepressant during the second and/or third trimester, 13 would be diagnosed with autism, statistically speaking. And in a group of 1,000 babies who were exposed to an SSRI in the second and/or third trimester, 15 would have autism.

But, says Vigod, “it’s important to flip the numbers around.” Of that first group of 1,000 babies not exposed to antidepressants, 993 would not be diagnosed with autism. In comparison, among the 1,000 babies exposed to some kind of antidepressant in the second and/or third trimester, 987 would not suffer from an autism, while in the group exposed to an SSRI, 985 wouldn’t be affected.

An editorial published in JAMA Pediatrics also encouraged readers not to see the issue as black and white. “It makes no more sense to suggest that antidepressants should always be avoided than to say that they should never be stopped,” it reads.

But Bérard says the value of her study is that it adds weight to the growing body of evidence linking environmental exposure to antidepressants, which transmit to the fetus via the placenta, and development of autism in young children. A mother of three herself, Bérard says the links cannot be ignored, and “more studies are needed in different populations to make sure.”


Bérard’s advice to women concerned about depression in pregnancy is to plan treatments around pregnancy as best they can. She says the fact that use in the second and third trimesters made a difference likely points to a connection between the effects of the drugs on baby brain development. “Women need to know the facts,” says Bérard. “If a woman decides she’s willing to take the risk, that’s fine. But she needs to make an informed decision.”

If you’re dealing with depression in pregnancy or concerned you might be, talk to your doctor or health care provider. Since prenatal appointments can feel rushed, you may even want to book a special appointment just to chat about mental health questions.

Read more: Antidepressants during pregnancy: Support not stigma> Special needs: How to deal with the diagnosis> Autism and schizophrenia linked to father’s age (Updated)>

This article was originally published on Dec 14, 2015

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