No clear autism link to antidepressant use during pregnancy, large study finds

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The use of antidepressants while pregnant does not raise the children’s risk for developmental disorders such as autism, according to an analysis of data from more than 25 million pregnancies that appears to contradict assertions by U.S. Health Secretary Robert F. Kennedy Jr.

Kennedy has said, without evidence, that certain antidepressants pose such a risk to fetuses, and has also linked vaccines to autism, a debunked theory contrary to established science. The causes of autism are unclear. Scientists speculate that its neurological characteristics may develop in utero, when the fetal brain is being wired.

“Our study provides reassuring evidence that commonly used antidepressants do not increase the risk of neurodevelopmental disorders such as autism and attention deficit hyperactivity disorder in children,” study leader Dr. Wing-Chung Chang of the University of Hong Kong said in a statement.

The researchers analyzed data from 37 earlier studies involving nearly 650,000 pregnancies with antidepressant use and nearly 25 million unexposed pregnancies.

Children of mothers who took antidepressants in pregnancy were slightly more likely to be diagnosed with autism or ADHD, they found. But the associations became significantly weaker, or statistically insignificant, after accounting for mothers’ mental health, family history, genetics, and other variables that could increase the risk of neurodevelopmental disorders, the researchers reported in The Lancet Psychiatry.

“This is a really important point that is easy to get wrong,” Dr. James Walker, professor emeritus of obstetrics and gynecology at the University of Leeds, who was not involved in the study, said in a statement.

“If you simply compare children whose mothers took antidepressants with children whose mothers did not, you may find a difference. But that does not mean the medicine caused the difference,” Walker said.

Risks not associated with pregnancy

Higher risks for autism and ADHD were also seen in children whose fathers used antidepressants while mothers were pregnant, and in those whose mothers had used them before, but not during, pregnancy, further suggesting that use in pregnancy did not explain the increased risks, the researchers said.

“A father’s medication obviously cannot reach the baby in the womb, so this pattern is very hard to explain by anything other than shared family traits,” Walker said.

Higher doses of antidepressants did not increase children’s risks, he said, which is another reason to doubt that the medicines are to blame.

In women with pre-existing mental health disorders, the older antidepressants amitriptyline and nortriptyline were linked with increased ADHD and autism risk in children. Those drugs are typically reserved for patients whose depression hasn’t responded to other treatments, suggesting that women treated with them may have had more complicated mental health conditions that could have influenced their children’s risks for ADHD and autism, the researchers said.

Amitriptyline and nortriptyline are so-called tricyclic antidepressants. They do not belong to the class of widely used antidepressants that Kennedy has most heavily criticized as a cause of adverse pregnancy outcomes, which are known as selective serotonin reuptake inhibitors, or SSRIs.

For pregnant women with mild depression, nonpharmacological treatments such as psychotherapy might be preferred, the researchers said. But antidepressants should never be withheld during pregnancy solely because of inconsistent and potentially confounded reports of neurodevelopmental risk, they added.

“Abrupt discontinuation might worsen maternal depression, which in itself is associated with adverse outcomes for both mothers and children,” they said.

In the U.K., mental health disorders are the leading cause of maternal mortality in the year following childbirth, said Dr. Anita Banerjee, an obstetrician at King’s College London who was not involved in the study, reinforcing that undertreated maternal mental illness carries its own serious risks.

Reporting by Nancy Lapid; Editing by Bill Berkrot, Reuters