Link between autism and infections during pregnancy explored
November 12th, 2012
02:57 PM ET

Link between autism and infections during pregnancy explored

If a mother has an infection or the flu during pregnancy, can it raise the risk of autism for her child? A new study out of Denmark suggests that the answer is "probably not" and "maybe" and that the issue definitely needs more study.

"Overall, we found little evidence that various types of mild common infectious diseases or febrile episodes during pregnancy were associated with ASD/infantile autism (autism spectrum disorders)," the study authors wrote.

But they also say their data suggest there are three scenarios in which there might be an increased risk of the child developing autism. If the mother had the flu, there was "a two-fold increased risk of infantile autism; if the mom had "prolonged episodes of fever" (lasting a week or more), the risk goes up threefold; "and use of various antibiotics during pregnancy were potential risk factors for ASD/infantile autism."  

But the study authors also concede that the results may be skewed by multiple testing, contributing to the potential for “chance findings.”

The study

These results of this study – published Monday in Pediatrics, the journal of the American Academy of Pediatrics - are based on researchers interviewing the mothers of 96,736 children born in Denmark between 1997 and 2003.

These women were asked nearly 200 questions in phone interviews around the 17th week of pregnancy, the 32nd week of pregnancy and six months after giving birth, long before any child could have been diagnosed with autism. This aimed to eliminate "recall bias," which can occur in studies where subjects self-report on their health. These women were asked whether they had any infections or episodes of fever and for how long, and whether they had taken any antibiotics.

The results

Among the over 96,000 children born, 976 were later diagnosed with autism spectrum disorders. The main signs and symptoms of autism involve difficulties with communication, social interactions and repetitive behaviors. According to the latest statistics from the U.S. Centers for Disease Control and Prevention, one in 88 children currently is diagnosed with autism, including one in 54 boys.

The study authors themselves note that a recently published Swedish study, which used inpatient hospital register data, "found no association between any prenatal infection and ASD."

The takeaway

“An important message is that even though we find an increased risk of ASD after influenza and prolonged periods of fever during pregnancy, the study is still speculative,” lead study author Dr. Hjördis Osk Atladottir said in an e-mail. “It is important to bear in mind that when you look at the absolute numbers, we see that around 99% of women reporting to have had influenza or fever during pregnancy do not have children with ASD. We do not want pregnant women to worry. Our results are truly explorative.”

She and her co-authors strongly recommend further research in this area.

In the meantime, Dr. Max Wiznitzer, a child neurologist at Rainbow Babies & Children's Hospital in Cleveland, says that since this study suggests the possibility of an association between influenza and autism, it reinforces the recommendation that pregnant women should get a flu shot, as recommended by the CDC.

soundoff (11 Responses)
  1. Doc Rick

    This study does not explain the autism epidemic. As we know from the recent Nature studies, men are passing autism at 4 times the rate of women (O'Roak BJ et al 2012). That means men are driving 80% of autism being passed to children, so we need to shift away from looking at autism being caused after conception.

    About 20 years ago, autism began mysteriously spiking up. Research now points to fragmentation in men's sperm cells as the major cause (Sanders SJ et al 2012). About 20 years ago, men began carrying radiation-emitting cell phones around in their front pockets, within a few inches of sperm cells. Cell phone radiation causes sperm cell DNA fragmentation (De Iuliis G 2009).

    Women, have him keep his cell phone out of his pockets for 30 days before you try! http://www.WhyAutismHappens.com

    November 12, 2012 at 16:13 | Report abuse | Reply
  2. Doc D

    Hi Doc Rick – what is this cell phone theory of yours based on? Also, individuals with autism/ASD were certainly born prior to the invention of cell phones. Likewise, children with autism are also born to parents who never used cell phones. And what is this advertising you are promoting on such a serious subject?

    November 12, 2012 at 17:09 | Report abuse | Reply
  3. Doc Rick

    @Doc D. I provided 3 scientific studies, plus a URL with over 5 more studies. You provide 0 scientific studies, make accusations against my character, and say "what is this theory of yours based on?" Moreover, the concerns you raise are answered in the very first paragraphs of the URL, so I see your time is too valuable to go any deeper. I have not the time to respond to you, sir.

    November 12, 2012 at 19:15 | Report abuse | Reply
    • I call BS

      Doc Rick is not a real doctor, nor does he play one in Trollville.

      November 12, 2012 at 20:36 | Report abuse |
    • Doc D

      Doc Ric – the studies you linked us to do not provide any literature that reveals the mechanism of how cell phone use can lead to autism. Moreover, there were people with autism way before cell phones were invented. To even begin to provide evidence for this association you suggest, you would have to follow a cohort over time to distinguish whether fathers who use cell phones prior to contraception have significantly higher incidences of children with autism in comparison to fathers who do not use cell phones. Furthermore, nowadays most fathers use cell phones, yet way less than 1 out of 88 children diagnosed with autism are conceived to such fathers. It seems that something outside of cell phone usage is making autism present in 1 of 88 children by age 8. Basically, there is a lack of logic and certainly evidence to just assume or even theorize that cell phone use of the father can be attributed to birthing autistic children. You should take at least a beginner's course in Epidemiology before you make such confident assertions.

      November 13, 2012 at 00:15 | Report abuse |
    • lola

      I use my iPhone when at work and my phone and computer at home. I like the cninevoence of my phone. Especially at work where I don't have to worry about web filters. I hate web sites that don't have the same information on their regular web site compared to the mobile site.

      December 18, 2012 at 17:08 | Report abuse |
  4. dayleft

    Over weight? http://majorityreviews.com/go/fatlossfactor

    November 12, 2012 at 23:11 | Report abuse | Reply

    He is not saying that it was ALWAYS caused by cell phones. It is a syndrome that has several genetic loci that are at the basis of it. Thus, there are more than one pathway to autism. There has not been one factor shown to directly cause it and it is the result of many. What researchers are trying to do is to find factors associated with higher incidences and then determine how they are causing the effect. The goal is to determine what cellular pathways they have in common and then be able to determine therapy or preventive measures to reverse or prevent.

    November 13, 2012 at 19:40 | Report abuse | Reply
  6. Max Caufield

    Wow, there must have a tremendous upsurge in autism after the 1918 flu pandemic!!! But wait, there wan't one. So, how do you explain that?

    November 14, 2012 at 16:11 | Report abuse | Reply
    • I call BS

      Well, maybe because nobody had ever HEARD of "autism" then. The word "autism" only dates from 1910, dear. I doubt most people had a clue about it, and children who had it probably were considered retarded or mentally ill at the time. Sheesh.

      November 16, 2012 at 18:16 | Report abuse |
  7. Nadia

    Neat Web site, Keep up the fantastic work. Thanks a ton.

    February 8, 2015 at 15:48 | Report abuse | Reply

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