It might seem like absolutely everyone is trying to figure out what causes autism spectrum disorder (ASD). Of course, one in 68 children has an ASD diagnosis, according to the CDC. With stats like that, it’s no wonder why so many autistic people and parents want to know why. Weeding through all of the junk science and not-so-well-tested, so-called “facts,” the “answer” still isn’t completely clear. But a new study recently found evidence connecting maternal infections during pregnancy with an increased chance of having an autistic child.

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The Study

Unless you’ve been living in a non-internet-connected, no-cell-service cave, chances are you’ve heard about this recent study. Researchers from Columbia University Mailman School of Public Health reviewed data from just under 96,000 children who were born between the years 1999 and 2009 in Norway.

Of the children included in the study, 583 were eventually diagnosed with ASD. Along with that, just over 15,700 of the mothers had fevers during pregnancy. The researchers found that women who had fevers during pregnancy were more likely to have an autistic child. But it wasn’t just one fever or fevers at any random point in pregnancy that raised a flag. The study found a link between specifically when and how many fevers a woman had and higher odds of ASD.

Second Trimester Influence

The Columbia researchers found that mothers who had three or more fevers after 12 weeks gestation experienced the greatest chance of having an autistic child. After analyzing the data, study researchers found that mothers-to-be who had one or two fevers during pregnancy were 1.3 times more likely to give birth to a child who would later be diagnosed with autism. When the woman had three fevers, the odds doubled.

Even though researchers aren’t 100 percent sure how maternal fevers during pregnancy and a child’s ASD diagnosis are connected, this theory doesn’t mean infections are causing autism. The specific virus or bacteria that’s making mom sick probably isn’t what’s raising the autism chances here. Instead, the thinking is that the infectious agent that triggers the immune response (the fever) may in some way affect the growing baby’s brain development.

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Fever Reduction

If it is the immune response that is raising the autism odds for the baby, it stands to reason that reducing the fever may also lower the chance that there is some sort of developmental change. And the study did find that women who took acetaminophen (e.g., Tylenol) to lower their fevers were less likely to have a child who would eventually be diagnosed with autism than moms who didn’t take the meds.

Even though the researchers believe there might be a connection here, the numbers weren’t significant enough to show a true relationship. So, if you’re preggo and have a fever, don’t go dosing yourself with tons of Tylenol. Always talk to your medical provider if you’re sick or think you should take medication during pregnancy. And keep in mind, this study poses one possible connection or cause. Right now scientists are still testing it out. In other words — it’s a promising hypothesis, but not a fact.

Other Research

This certainly isn’t the first study posing that there is a “cause” for autism. Aside from the now debunked vaccine-autism connection, plenty of other researchers have tested their theories on environmental and health factors that may raise the odds.

In 2014, researchers from the University of California, Davis published a study in the Journal of Autism and Developmental Disorders that also found a connection between maternal fevers and children with autism. Like the large-scale data analysis of the Columbia study, this one only included 538 children who were already diagnosed with ASD, 163 diagnosed with developmental delays, and 421 typically developing children. The researchers looked at whether influenza and/or fevers during pregnancy had any connection to autism. While maternal flu during pregnancy wasn’t connected to the child later developing autism, fevers were.

What do you think about this new research? Tweet us @BritandCo!

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