Autism Link to Flu in Pregnancy is Weak

Infection and flu during pregnancy show no strong link to autism in children

(RxWiki News) Getting sick while pregnant may make expectant moms feel even more ill at ease. Will the illness affect your child? Can it increase his or her risk of autism? So far, it seems unlikely.

A recent study looked at whether autism was linked to infections during pregnancy. The researchers found little evidence to say it was. But this study's results were inconclusive.

The best way to avoid the flu during pregnancy is to get a flu shot and to frequently wash your hands.

"Pregnant? Get your flu shot."

The study, led by Hjördis Ósk Atladóttir, MD, PhD, of the Department of Public Health at the University of Aarhus in Denmark, aimed to find out whether there was a link between autism and a mother having an infection or fever during pregnancy.

The researchers used data from 96,736 children born in Denmark between 1997 and 2003. The mothers of these children were interviewed while they were pregnant or shortly after giving birth. The women were asked whether they had had a fever or an infection while pregnant or whether they had used antibiotics up through their 32nd week of pregnancy.

The women were never directly asked whether they had respiratory disease or the flu while pregnant. However, the researchers used the other questions to derive whether the women were likely to have had influenza.

Then the researchers looked at diagnoses of the children for autism spectrum disorders when they were 8 to 14 years old. Overall, 976 children (equal to about 1 percent) had been diagnosed with an autism spectrum disorder. This rate is similar to the expected standard rate in any population.

Using their estimates of who likely had influenza, the researchers found that women who appeared to have the flu also had a higher risk of having a child with autism.

However, the link was not strong enough for them to be certain that the results were not a coincidence. In other words, even though the risk appeared higher, the results could have been due to chance.

The researchers also found a higher likelihood of autism among the children of women who had a fever for a week or longer. Again, however, the results could have been due to statistical chance.

In addition, a significant limitation of this study is that all the women were reporting their own health by phone.

The researchers attempted to confirm their reports with hospital records, but the women may not have gone to a doctor or hospital for many of their complaints.

Also, the way a person reports their own health may not be the same way that a medical professional will assess it. Some women may downplay their symptoms, and others may exaggerate.

The researchers therefore had to conclude that they "found little evidence that various types of mild common infectious diseases or febrile episodes during pregnancy were associated with autism spectrum disorders/infantile autism."

Even though this study did not find a strong link between influenza during pregnancy and autism, they found a weak connection.

The study was published November 12 in the journal Pediatrics. The research was funded by Aarhus University Research Foundation, the Aase and Ejnar Danielsen Foundation and the Augustinus Foundation. The authors declared no conflicts of interest.

Review Date: 
November 11, 2012