Is SSRI use during pregnancy an autism risk factor?

23 Dec

A few recent studies have suggested that using SSRI’s during pregnancy might increase the risk of a child later being diagnosed autistic. SSRI’s are commonly used to treat depression.

Earlier this year a team from Bristol studied the question and concluded:

In utero exposure to both SSRIs and non-selective monoamine reuptake inhibitors (tricyclic antidepressants) was associated with an increased risk of autism spectrum disorders, particularly without intellectual disability. Whether this association is causal or reflects the risk of autism with severe depression during pregnancy requires further research. However, assuming causality, antidepressant use during pregnancy is unlikely to have contributed significantly towards the dramatic increase in observed prevalence of autism spectrum disorders as it explained less than 1% of cases.

In other words, mothers taking SSRI’s may have more autistic children (50% increased risk) but that could be due to the underlying condition (depression) rather than the SSRI use.

A previous study pointed to an exposure risk from SSRI’s:

Although the number of children exposed prenatally to selective serotonin reuptake inhibitors in this population was low, results suggest that exposure, especially during the first trimester, may modestly increase the risk of ASD. The potential risk associated with exposure must be balanced with the risk to the mother or fetus of untreated mental health disorders. Further studies are needed to replicate and extend these findings.

This past week another study was published: Use of selective serotonin reuptake inhibitors during pregnancy and risk of autism. This tells a slightly different story: no increased risk for SSRI use during pregnancy, but an increased risk for mothers who used SSRI’s before pregnancy but not during. That would be consistent with the group above who postulated “Whether this association is causal or reflects the risk of autism with severe depression during pregnancy requires further research. ”

A good discussion of this work is found at the Simons Foundation SFARI website: Study challenges link between antidepressants, autism.

I’ve seen people state emphatically based on the earlier work that SSRI’s should be banned for pregnant women. The present study shows how problematic drawing such strong conclusions from these small studies can be. What if the risk is for women who stop SSRI use?

The authors of the present study note that more work is warranted. This is clearly the case as the studies to date are conflicting and use small populations.

Here is the abstract from the present study:

Studies have raised concern about an association between the use of selective serotonin reuptake inhibitors (SSRIs) during pregnancy and an increased risk of autism spectrum disorders in the offspring.
We conducted a cohort study of all singleton live births in Denmark from 1996 through 2005 (626,875 births), with follow-up through 2009. Using Danish population registries, we linked information on maternal use of SSRIs before and during pregnancy, autism spectrum disorders diagnosed in the offspring, and a range of potential confounders. We used a survival analysis of the time to diagnosis in the offspring with Poisson regression to estimate rate ratios of autism spectrum disorders according to maternal use of SSRIs.
During 5,057,282 person-years of follow-up, we identified 3892 cases of autism spectrum disorder (incidence rate, 77.0 per 100,000 person-years). A total of 52 cases during 42,400 person-years of follow-up involved offspring of women who were exposed to SSRIs during their pregnancy (incidence rate, 122.6 per 100,000 person-years). As compared with no use of SSRIs both before and during pregnancy, use during pregnancy was not associated with a significantly increased risk of autism spectrum disorders (fully adjusted rate ratio, 1.20; 95% confidence interval [CI], 0.90 to 1.61). Among women who received SSRIs before pregnancy but not during pregnancy, the corresponding fully adjusted rate ratio was 1.46 (95% CI, 1.17 to 1.81).
We did not detect a significant association between maternal use of SSRIs during pregnancy and autism spectrum disorder in the offspring. On the basis of the upper boundary of the confidence interval, our study could not rule out a relative risk up to 1.61, and therefore the association warrants further study. (Funded by the Danish Health and Medicines Authority.)

By Matt Carey

3 Responses to “Is SSRI use during pregnancy an autism risk factor?”

  1. autisticook December 23, 2013 at 09:33 #

    Since women are often misdiagnosed with bipolar or depression instead of ASD, it wouldn’t surprise me at all if there is a link. But it’s not because of the SSRI use. And it’s not because of depression. I’d say it’s because of undiagnosed ASD.

    It’s a bit like that “older fathers/mothers” myth. Having social challenges makes it more likely that you’ll have children later than average, simply because it takes you more time to find someone to have them with.

    • chavisory December 23, 2013 at 21:52 #

      I was just going to say just about the same thing. Did they screen both parents and grandparents for undiagnosed autism or autistic traits? Aside from possible misdiagnosis with bipolar disorder or depression, the social isolation and compromised quality of life of living with undiagnosed autism can *cause* depression. Add to that that autistic women suffer rates of physical, sexual, and emotional abuse of over 90%…and are women with strong autistic traits simply more likely to wind up on SSRI’s?

      • Lawrence December 27, 2013 at 12:46 #

        Groups like “AoA” don’t want to hear about genetic pre-disposition for autism…especially in light of women showing different symptoms than men (interesting hypothesis that depression could be a trait of female autism)….

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