Prenatal Exposure to Fever May Lead to Autism, Study Finds

Children with autism often see things more clearly, hear things more loudly, smell things more strongly, feel things you don't, and taste things differently. Once a highly stigmatized and rarely understood disability, autism spectrum disorder has received a wealth of attention and research over the past decade, and one recent study from Columbia University may show an important link between a pregnant woman having fevers and her increased chance of having a baby with autism spectrum disorder (May, 2017).

The Study

Research released by the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health has shown that prenatal exposure to a fever during the pregnancy may increase the chance of a baby having autism (As cited in Hornig et al., 2017).

The researchers at Columbia University followed nearly 96,000 children born between 1999 and 2009, which included 583 cases of confirmed autism spectrum disorder as identified in Norway by the Autism Birth Cohort Study. The mothers of almost 16,000 children had reported having a fever in one or more four-week intervals throughout their pregnancy, which is similar to rates reported in U.S. studies ("Autism Risk Linked to Fever During Pregnancy," 2017).

The risk for autism increased by 34 percent by the mothers who reported having a fever over 99 degrees at any time during the pregnancy. This risk grew to 40 percent for mothers who reported that their fever took place during the second trimester. Of all of the women who participated, those who reported having a fever during or after the twelfth week of pregnancy turned out to have increased their child's risk for having autism spectrum disorder by more than 300 percent (As cited in May, 2017).

The study had intended to explore the risk of autism spectrum disorder associated with fevers across the entire pregnancy, and of the capacity to use two commonly used anti-fever medications (ibuprofen and acetaminophen) to address the risk. The risks were all minimally mitigated among the infants of mothers taking acetaminophen for the fever in the second trimester. Although the reports revealed that there were no cases of autism among the mothers who did, indeed, take ibuprofen, the sample was so small that no declarations could be made confirming the use of the medication to prevent autism in whole.

"Our results suggest a role for gestational maternal infection and innate immune responses to infection in the onset of at least some cases of autism spectrum disorder," said Hornig, associate professor of Epidemiology and Director of Translational Research at CII.

Although it does appear that the questionnaire analysis did not indicate whether there was an association between risk and maternally reported symptoms of infection in the mother's individual organ systems so one cannot implicate specific infections agents in measuring risk.

"Future work should focus on identifying and preventing prenatal infections and inflammatory responses that may contribute to autism spectrum disorder," says W. Ian Lipkin, John Snow Professor of Epidemiology and director of CII.

Implications

This recent study by Columbia University is huge news for the autism world, especially after the Centers for Disease Control and Prevention (CDC) released their findings that more than 2.2 percent of children between the ages of 3 and 17 (i.e., about 1 in 45) will have an autism spectrum disorder (As cited in Szabo, 2015).

The CDC's National Health Interview Survey was conducted in 2014 and found that the rate had grown that by nearly 1.03 percent since the 2013 survey.

A major reason for the dramatic increase in autism spectrum disorder rates in the latest survey may suggest that parents use different labels now to describe their children than they had in previous years when the disorder was less understood, said Katherine Walton, assistant professor of psychiatry and psychology at Ohio State University.

The reasoning behind this theory is that while the number of children that were reported to have autism increased, the total number of children that were reported to have "other developmental delays" decreased. However, the entire pool of parents who reported that their child had at least some degree of developmental disability in their kids remained the same (around 5.75 percent) (As cited in Szabo, 2015).

Other Risk Factors

While no single factor has been identified to cause autism spectrum disorder in children, several previous research studies have revealed a few other risk factors that seemed to increase the chance of a child developing a diagnosis on the autism spectrum: older parents, premature or low birth weight, and second children conceived less than a year from the first-born children.

Older Parents

This study used data from 10 US study sites participating in the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring Network. The cases included 1,251 children who were 8-years-old and had been identified as having an autism spectrum disorder. The study found that the first-born offspring of 2 parents older than 40 were 3 times more likely to develop autism than later-born offspring of parents under 40
(Durkins et al., 2008).

Babies Born Prematurely or At a Low Birth Weight

This study reviewed the prevalence of autism spectrum disorder in children born between 1981 and 1993 and who were between 3 and 10. The research revealed that in pregnancies where a female's birth weight was under 2500 g and was born before 33 weeks, she was more than twice as likely have autism spectrum disorder later on than boys or girls who were born with higher birth weight and further along in development (Schendel and Bhasin, 2007).

Second-Born Conceived Less Than One Year from First-Born

This research studied full siblings that were born in pairs (first-borns and second-borns). The research revealed that in cases where the second child was conceived less than a year from the first-born child that the second-born child's chance at having autism increased regardless of birth-weight, prenatal developmental stage, and age of parents.

Resources

Autism Speaks
www.autismspeaks.org

Autism Society of America
www.autism-society.org

National Autism Association
http://nationalautismassociation.org/

National Institute of Health
https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Autism-Spectrum-Disorder-Fact-Sheet

Centers for Disease Control and Prevention
https://www.cdc.gov/ncbddd/autism/index.html

References

"Autism Risk Linked to Fever During Pregnancy" (2017, June 13). [Web]. EurekAlert. Retrieved from: https://www.eurekalert.org/pub_releases/2017-06/cums-arl060717.php

Durkin, M., Maenner, M., Newschaffer, C., Lee, L., Cunniff, C., . . . Schieve L. (2008). Advanced parental age and the risk of autism spectrum disorder. American Journal of Epidemiology. [Web]. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/18945690

Hornig, M., Bresnahan, M., Che, X., Schultz, A., Ukaigwe, J., Eddy, M., . . . Lipkin, W. (2017). Prenatal fever and autism risk. In Molecular Psychiatry. [Advance Online Publication]. Retrieved from: http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2017119a.html

May, A. (2017, June 14). Autism risk increases 34% if mom has a fever while pregnant, study says. [Web]. In USA Today. Retrieved from: https://www.usatoday.com/story/news/nation-now/2017/06/14/autism-risk-increases-34-if-mom-has-fever-while-pregnant-study-says/395324001/

Schendel, D., & Bhasin, T. (2007). Birth weight and gestational age characteristics of children with autism, including a comparison with other developmental disabilities. [Web]. In Pediatrics. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/18519485

Additional Information

The study was funded by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health (NS47537, NS086122), the Jane Botsford Johnson Foundation, Simons Foundation Autism Research Initiative, the Norwegian Ministry of Health and Care Services, the Norwegian Ministry of Education and Research, and the Research Council of Norway.

Co-authors include Xiaoyu Che, Michaeline A. Bresnahan, Andrew F. Schultz, Joy E. Ukaigwe, Meredith L. Eddy, Bruce Levin, and Ezra S. Susser at Columbia; Deborah Hirtz at the National Institute of Neurological Disorders and Stroke; and Nina Gunnes, Kari Kveim Lie, Per Magnus, Siri Mjaaland, Ted Reichborn-Kjennerud, Synnve Schjølberg, Cand Psychol, Anne-Siri Øyen and Camilla Stoltenberg at the Norwegian Institute of Public Health.