Autism Spectrum Disorders: Bacterial Infections During Pregnancy Increased Risk

Dr. Lisa Croen, PhD Senior Research Scientist Director, Autism Research Program Division of Research Kaiser Permanente Northern Interview with
Dr. Lisa Croen, PhD
Senior Research Scientist
Director, Autism Research Program
Division of Research
Kaiser Permanente Northern California What are the main findings of the study?

Dr. Croen: Researchers found that hospital-diagnosed maternal bacterial infections during pregnancy were associated with an increased risk of autism spectrum disorders (ASD) in children. While infections are fairly common in pregnant women, this study only found increased risks in cases of bacterial infections. Women with bacterial infections diagnosed during a hospitalization (including of the genitals, urinary tract and amniotic fluid) had a 58 percent greater risk of having a child with ASD.

Also of note, bacterial infections diagnosed during a hospitalization in the second trimester, while not very common in any of the mothers studied, were associated with children having more than a three-fold increased risk of developing ASD.

These findings resulted from a study of 407 children with autism and 2,075 matched children who did not have autism. The study included infants born between January 1995 and June 1999 who remained members of the Kaiser Permanente health plan for at least two years following birth. Were any of the findings unexpected?

Dr. Croen: Previous studies indicate that prenatal exposure to viral infections is a possible pathway through which autism spectrum disorders could be initiated in some children.  In our study, we did not find an association between maternal viral infections during pregnancy and risk of ASD in children.

By contributing new evidence to a body of scientific literature on the role of infection in autism risk, these findings broaden our understanding of which types of infections are associated with risk of autism spectrum disorders. What should clinicians and patients take away from your report?

Dr. Croen: For clinicians, the most important take away is to communicate with their patients about the importance of reporting when they suspect an infection.  For patients, it is critical that they contact their physician as soon as they suspect an infection so that it can be properly diagnosed and treated. What recommendations do you have for future research as a result of this study?

Dr. Croen: Future studies should be conducted to understand the underlying biologic mechanisms that are responsible for the association between bacterial infections and increased risk of ASD.


Maternal infection requiring hospitalization during pregnancy and autism spectrum disorders.

J Autism Dev Disord. 2010 Dec;40(12):1423-30. doi: 10.1007/s10803-010-1006-y.
Atladóttir HO, Thorsen P, Østergaard L, Schendel DE, Lemcke S, Abdallah M, Parner ET.


Last Updated on January 7, 2014 by Marie Benz MD FAAD