Both antidepressant use and autism spectrum disorder (ASD) diagnoses have increased over the last several decades.1,2 The coincidental timing of these increases have led to the hypothesis that antidepressant use during pregnancy may be related to the increase in ASD diagnoses. Some previous studies have shown a possible causal link while others have not.3–5
To better understand whether antidepressant use during pregnancy increases the risk of children developing ASD, we first examined the effect of prenatal maternal depression on the development of ASD in 824,549 children whose mother did not have an antidepressant prescription during pregnancy. We compared the rate of ASD between those born to mothers with and without depression, as shown in Figure 1. Children whose mother had depression were 54.9% more likely to be diagnosed with ASD than those whose mother did not have depression during pregnancy. We did not assess how behavioral, environmental, or genetic factors surrounding maternal depression may affect the risk of a child developing ASD as part of this study.
We then examined how the use of antidepressants during pregnancy affects the risk of ASD diagnosis compared to the risk from depression alone, as shown in Figure 2. We studied 50,976 children who were born to mothers who had an active prescription for antidepressants at some point during pregnancy and compared them with the 824,549 children who were born to mothers who did not have an antidepressant prescription during pregnancy. While there is a slightly higher risk for children whose mother was prescribed antidepressants during the second or third trimesters, this increase is not statistically significant. These increases may be caused by confounding factors, such as severity of depression, rather than an effect of the medication.
Comparisons between different classes of antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) and selective norepinephrine reuptake inhibitors (SNRIs) did not show significant differences in ASD rates. Comparisons between siblings where the mother had an antidepressant prescription during one pregnancy but not the other also showed no significant difference. These findings are consistent with some previous research that showed any effect of antidepressant use during pregnancy on the development of ASD is small.5
