Pregnant women who experience a bacterial infection while in a hospital may be at higher risk for having a child with autism, according to a new study. Infections during pregnancy are common and most infections do not increase the risk for autism. Only bacterial infections diagnosed in the hospital were associated with an increased risk for the disorder.

Published in the Journal of Autism and Developmental Disorders, the study shows an association between infection and autism spectrum disorders, a group of conditions known collectively as ASD. Scientists from Kaiser Permanente Division of Research examined the records of 407 children with autism and 2,075 kids without the condition. Born between 1995 and 1999, all the children were part of a Kaiser Permanente health plan for at least the first two years of life.

The researchers found that women who received a diagnosis of bacterial infection while in the hospital had a 58 percent higher risk of having a child with ASD. Furthermore, the scientists found that receiving an inpatient diagnosis of bacterial infection during the second trimester, while rare, tripled the risk for ASD.

Bacterial infections common among pregnant women admitted to hospitals include those affecting the genitals, urinary tract, and amniotic fluid. Author of the study Dr. Ousseny Zerbo explains that infections diagnosed in a hospital might be associated with ASD because the infection might be more severe.

Scientists do not yet know how bacterial infections increase the risk for ASD but some speculate the mother’s immune system reacts to the infection in a way that interferes with fetal brain development. Studies show viral infections disrupt the neural development of mice and rats in a way that increases the risk for ASD.

The authors of the study stress that most bacterial infections do not increase the risk for autism but do suggest that pregnant women contact a doctor if they think they have an infection. Symptoms of a bacterial infection may include abnormal vaginal discharge, an unpleasant odor, painful urination, cloudy or bloody urine, fever, and increase heart rate for either the mother or her baby.


  1. Paddock, Catharine. "Hospital infection in pregnancy tied to higher risk of autism." Medical News Today. MediLexicon, Intl., 24 Dec. 2013. Web. 10 Jan. 2014.
  2. University of California - Davis Health System. "How viral infection disrupts neural development in offspring, increasing risk of autism." Medical News Today. MediLexicon, Intl., 30 Sep. 2013. Web. 10 Jan. 2014.