Autism risks are increased if the mother had the flu during pregnancy says a new study.
Researchers in Denmark and the US found that women who had the flu during pregnancy doubled the risk of having a child with autism.
The study suggests that having a high fever during pregnancy may be the reason why, reported ABC News, but causation has still not been established.
WebMD reported that previous animal studies have shown that the presence of an infection in the mother during pregnancy could affect the fetal brain.
The new findings come from a study looking at 97,000 children between the ages of eight and 14 who were born in Denmark.
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Only about one percent of them were diagnosed with autism.
The researchers had interviewed the women during and after their pregnancy about their health.
Austism risk doubled in those reporting that they had the flu during pregnancy.
They also found that the risk of autism was increased by three if the woman had the flu that persisted for more than one week, said USA Today.
The study reaffirms the recommendation by doctors that women should always have a flu shot during pregnancy, though the study did not establish whether the vaccination would have prevented the autism.
The study was published in the journal Pediatrics.