Boys, whose mothers took antidepressants such as Lexapro, Paxil, Prozac or Zoloft while pregnant, were almost three times more likely to have autism spectrum disorder.
Rebecca A. Harrington and Li-Ching Lee of the Johns Hopkins Bloomberg School of Public Health, Dr. Rosa M. Crum of Johns Hopkins Medical Institutions, Dr. Andrew W. Zimmerman of the University of Massachusetts Medical School and Irva Hertz-Picciotto of the University of California, Davis, said the study involved a total of 966 mother-child pairs.
Using data from the Childhood Autism Risks from Genetics and the Environment Study, 492 children had autism spectrum disorder, 154 children had developmental delays and 320 children had typical development.
The study, published online in Pediatrics ahead of the May print issue, found prenatal exposure to the antidepressants was lowest -- 3.4 percent -- in children that developed typically, but rose to 5.2 percent of children with developmental delays and higher still at 5.9 percent of children with autism spectrum disorder. The strongest association was in the first three months of pregnancy.
"In boys, prenatal exposure to selective serotonin re-uptake inhibitors, a class of compounds used as antidepressants to treatment of depression, anxiety and some personality disorders, might increase susceptibility to autism spectrum disorder or developmental delays," the researchers wrote in the study.
"Potential recall bias and residual confounding by indication are concerns. Larger samples are needed to replicate developmental delays results. Because maternal depression itself carries risks for the fetus, the benefits of prenatal SSRI use should be carefully weighed against potential harms."