Antidepressant use during pregnancy may be linked to autism

Croen L. Arch Gen Psychiatry. 2011;doi:10.1001/archgenpsychiatry.2011.73.

Babies born to mothers who were prescribed certain antidepressants during their pregnancies had a twofold increased risk for autism spectrum disorders compared with controls, according to a CDC-funded study published online this week.

Lisa Croen, PhD, director of the Autism Research Program at the Kaiser Permanente Division of Research in Oakland, Calif., and colleagues looked at 298 children with autism spectrum disorders (ASD) and 1,507 randomly selected control children drawn from the Kaiser Permanente Northern California membership. The researchers collected information on maternal use of antidepressant medications, maternal mental health history, autism and demographic characteristics.

The researchers reported that in utero exposure to antidepressant medications was reported in 6.7% of cases and 3.3% of controls. Mothers of children subsequently diagnosed with ASD were twice as likely to have at least one antidepressant prescription in the year before delivery of the study child, and more than three times as likely to have a prescription in the first trimester of pregnancy.

“Our results suggest a possible, albeit small, risk to the unborn child associated with in utero exposure to selective serotonin reuptake inhibitors (SSRIs), but this possible risk must be balanced with risk to the mother of untreated mental health disorders,” Croen said in a press release about the findings.

In a subgroup analysis, the researchers looked at women with a history of mental health disorders in the year before delivery. Risk of ASD associated with SSRI use anytime during this year remained somewhat elevated in this subgroup, but did not reach statistical significance.

Prior studies have indicated that abnormalities in serotonin levels and serotonin pathways may play a role in autism. Collectively, these studies suggest the possibility that prenatal SSRI exposure may operate directly on the developing brain, perhaps selectively in fetuses with abnormalities in serotonin-related genes, Croen said, adding that physiologic changes related to maternal stress or depression during pregnancy combined with SSRI exposure may contribute to changes in fetal brain development, leading to later-diagnosed ASD.

Disclosures: The research was supported by a Kaiser Permanente Community Benefit Research Fund and by the CDC. It is part of ongoing body of autism research being conducted at the Kaiser Permanente Division of Research. The researchers reported no relevant financial disclosures.

Suzanne Dixon, MD, MPH

This study is part of a huge and ever-growing body of reports on the links to ASD with various risk conditions. There clearly is an increase in the true incidence of autism in the US, not completely explained by enhanced diagnostic criteria and awareness, but no one has the answer to explain this rise. And the pursuit of the explanations is hot and heavy.

Genetics clearly play a part in autistic disorders, but there continues to be exploration of the environmental linkages as well. This study highlights one association, which should not be assumed to be a cause of autism. A lot more work done prospectively would have to be done to establish a causal relationship between SSRI exposure during gestation and autism. The best minds seem to embrace, at this time, the notion that autism is likely an array of conditions caused by different factors, likely genetic, environmental and by the interaction between them, an epigenetic mechanism in most cases. The SSRI link needs more investigation, but in the meantime, many women will likely need these medications to function. There is also a huge body of research of the strong, negative effect of maternal depression on the cognitive and emotional health of children, so we need these medications for healthy families overall. Each case needs to be balanced out in individual patients, and any medication during pregnancy, including the SSRIs, should be taken only if needed and with careful consideration.

– Suzanne Dixon, MD, MPH
Infectious Diseases in Children Editorial Board member

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