Fever During Pregnancy Linked to Higher Autism Spectrum Disorder Risk

Any kind of sickness during pregnancy may be a cause for concern. But one new study suggests having a fever while pregnant could even lead to a higher risk for having a child with autism spectrum disorder.

During the second trimester specifically, the odds increased by 40 percent, according to a Columbia University Mailman School of Public Health study. Scientists at the school's Center for Infection and Immunity headed the study, which was published in Molecular Psychiatry.

Among the women followed for this study, a fever at any point during their pregnancy led to a 34 percent higher risk of having a child with autism spectrum disorder. Three or more fevers after the pregnancy's twelfth week meant a more than 300 percent higher risk of having a child with autism spectrum disorder, reports USA Today.

Autism spectrum disorder refers to a number of conditions associated with social, communication and behavior problems. The conditions include autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS) and Asperger syndrome, according to the Centers for Disease Control and Prevention.

Researchers examined 95,754 children for the study, all born from 1999 to 2009. There were 583 confirmed cases of autism spectrum disorder, per the Autism Birth Cohort Study in Norway. In the case of 15,701 children, their mothers said they had a fever in one or more four-week intervals during their pregnancy. This aligns with U.S. rates.

Mothers who took ibuprofen during pregnancy didn't have children with autism spectrum disorder, though researchers said the numbers involved making this observation were too small to definitively say whether their risk was lowered because of the drug.

Researchers also emphasized in the study that no cause-and-effect determination can be made through simply observational research, and that certain study numbers were small.

"We acknowledge that our findings are limited by small numbers, particularly for first- and third-trimester exposures to fever and antipyretics; replication in other populations will also be critical before determining the implications of this work for management of fever in pregnancy," according to the study.

As for what research should focus on next, "future work should focus on identifying and preventing prenatal infections and inflammatory responses that may contribute to autism spectrum disorder," study author W. Ian Lipkin said in a statement. He is also the director of the Center for Infection and Immunity.