Studies cast doubt on link between autism and antidepressant use in pregnancy

Two large studies have found no clear association between antidepressant use by pregnant women and the risk of autism in their children, suggesting that previous research showing a link may have been skewed by other factors.

In the first study, a team of researchers from Indiana University, United States, used a Swedish database of over 1.5 million infants to look at the relationship between using antidepressants in the first trimester and several neurodevelopmental problems.

Among the 22,544 infants whose mothers had taken antidepressants in the first three months of pregnancy, initial calculations showed an increased risk of preterm birth and being small for gestational age, and more than double the risk of autism and attention deficit hyperactivity disorder (ADHD).

But the researchers, reporting in JAMA
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found that only a small risk of pre-term birth — about 1.3 times higher — remained after controlling for several factors.

In the second study, Canadian researchers looked at the association between selective serotonin reuptake inhibitor (SSRI) use during pregnancy and childhood autism across almost 36,000 births.

Among the 2,837 pregnancies exposed to the drugs, there was an increased risk of autism diagnosis — again about double — but, once again, after confounding factors were taken into account, including a comparison with unexposed siblings, the difference was no longer significant^[2]
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The findings counter previous studies, which have suggested that antidepressant use may increase the risk of autism significantly, although a causal relationship cannot be ruled out, the researchers say.

Adding to the mixed picture, a meta-analysis published in JAMA Pediatrics
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(online, 17 April 2017) found an increased risk of autism in children whose mothers took antidepressants during the pre-conception period, highlighting the difficulty in unpicking the different factors involved.

Brian D’Onofrio from the Department of Psychological and Brain Sciences at Indiana University, led the research using Swedish data. He says: “To our knowledge, this is one of the strongest studies to show that exposure to antidepressants during early pregnancy is not associated with autism, ADHD or poor fetal growth when taking into account the factors that lead to medication use in the first place.”

He adds: “Balancing the risks and benefits of using antidepressants during pregnancy is an extremely difficult decision that every woman should make in consultation with her doctor.

“However, this study suggests use of these medications while pregnant may be safer than previously thought.”

Virginia Beckett, spokesperson for the Royal College of Obstetricians and Gynaecologists, says the three studies add to the growing body of literature on using antidepressants during pregnancy but says more research is warranted.

“These studies are based on observational data, which means no firm conclusions can be made about cause and effect.

“This is because it’s difficult to separate the effects of the drug treatment from other risk factors, such as maternal illnesses, which may have a role in the development of autism spectrum disorders and ADHD.”

She says that 12–20% of women experience anxiety and/or depression during pregnancy and within the first year of childbirth.

“The decision whether or not to use antidepressants during pregnancy must be considered on an individual basis.



“Untreated maternal depression can be very serious for a woman and can also impact her baby’s health.”