Antidepressants during pregnancy associated with increased autism risk

The use of antidepressants, especially selective serotonin reuptake inhibitors, during the final two trimesters of pregnancy was associated with increased risk for autism spectrum disorder in children, according to an article published online by JAMA Pediatrics. Antidepressants (ADs) are widely used during pregnancy to treat depression. Autism spectrum disorder (ASD) is a neurodevelopmental syndrome characterized by altered communication, language and social interaction and by particular patterns of interests and behaviors. Few studies have investigated the effect of AD use during pregnancy on the risk of ASD in children. A better understanding of the long-term neurodevelopmental effects of ADs on children when used during gestation is a public health priority.

Anick Bérard, Ph.D., of the University of Montreal, Canada, and coauthors used data on all pregnancies and children in Québec between January 1998 and December 2009. The authors identified 145,456 full-term singleton infants born alive. Of the infants, 1,054 (0.72 percent) had at least one ASD diagnosis; the average age at first ASD diagnosis was 4.6 years and the average age of children at the end of follow-up was 6.2 years. Boys with ASD outnumbered girls 4 to 1.

The authors identified 4,724 infants (3.2 percent) who were exposed to ADs in utero; 4,200 (88.9 percent) infants were exposed during the first trimester and 2,532 (53.6 percent) infants were exposed during the second and/or third trimester. There were 31 infants (1.2 percent) exposed to ADs during the second and/or third trimester diagnosed with ASD and 40 infants (1.0 percent) exposed during the first trimester diagnosed with ASD, according to the results.

The use of ADs during the second and/or third trimester was associated with an 87 percent increased of ASD (32 exposed infants), while no association was observed between the use of ADs during the first trimester or the year before pregnancy and the risk of ASD.

Results indicate the increased risk of ASD was observed with selective serotonin reuptake inhibitors (22 exposed infants) and with the use of more than one class of AD during the second and/or third trimester (five exposed infants). In children of mothers with a history of depression, the use of ADs during the second and/or third trimester was associated with an increased risk for ASD in the study (29 exposed infants).

The authors suggest several mechanisms may account for the increased risk of ASD associated with maternal use of ADs during pregnancy. Limitations to the study include its use of prescription filling data, which may not reflect actual use. The data also contained no information on maternal lifestyle.

"Further research is needed to specifically assess the risk of ASD associated with antidepressant types and dosages during pregnancy," the study concludes.

Source: The JAMA Network Journals