Antidepressant exposure in pregnancy and risk of autism spectrum disorders

Abstract

Merete Juul Sørensen,1 Therese Koops Grønborg,2 Jakob Christensen,3,4 Erik Thorlund Parner,2 Mogens Vestergaard,5,6 Diana Schendel,7 Lars Henning Pedersen8,9 1Regional Centre of Child and Adolescent Psychiatry, Aarhus University Hospital, Risskov, Denmark; 2Department of Public Health, Section of Biostatistics, Aarhus University, Aarhus, Denmark; 3Department of Neurology, Aarhus University Hospital, Aarhus, Denmark; 4Department of Clinical Pharmacology, 5Department of Public Health, Section of General Practice, 6Research unit for General Practice, Aarhus University, Aarhus, Denmark; 7Centers for Disease Control and Prevention, Atlanta, GA, USA; 8Danish Epidemiological Science Centre, Institute of Public Health, 9Department of Obstetrics and Gynecology, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark Background: Both the use of antidepressant medication during pregnancy and the prevalence of autism spectrum disorder have increased during recent years. A causal link has recently been suggested, but the association may be confounded by the underlying indication for antidepressant use. We investigated the association between maternal use of antidepressant medication in pregnancy and autism, controlling for potential confounding factors. Methods: We identified all children born alive in Denmark 1996–2006 (n=668,468) and their parents in the Danish Civil Registration System. We obtained information on the mother's prescriptions filled during pregnancy from the Danish National Prescription Registry, and on diagnoses of autism spectrum disorders in the children and diagnoses of psychiatric disorders in the parents from the Danish Psychiatric Central Register. In a cohort analysis, we estimated hazard ratios of autism spectrum disorders in children exposed to antidepressant medication during pregnancy compared with children who were not exposed, using Cox proportional hazards regression analysis. Furthermore, we estimated the risk for autism spectrum disorder in a sibling design. Results: Children exposed prenatally to antidepressants had an adjusted hazard ratio of 1.5 (95% confidence interval [CI] 1.2–1.9) for autism spectrum disorder compared with unexposed children. Restricting the analysis to children of women with a diagnosis of affective disorder, the adjusted hazard ratio was 1.2 (95% CI 0.7–2.1), and the risk was further reduced when exposed children were compared with their unexposed siblings (adjusted hazard ratio 1.1; 95% CI 0.5–2.3). Conclusion: After controlling for important confounding factors, there was no significant association between prenatal exposure to antidepressant medication and autism spectrum disorders in the offspring. Keywords: antidepressants, depression; autism, autism spectrum disorder, childhood autism, pregnancy