A new study conducted by researchers at the Mailman School of Public Health at Columbia University in New York discovered autism risks increased simultaneously with the number of fevers reported by mothers after 12 weeks of pregnancy. The risks increased by 300 percent when three or more fevers were reported.
The research team say their findings reinforces the belief that infection during pregnancy and how the immune system responds to the infection may be associated with the development of autism in some situations.
Autism spectrum disorder or ASD, a group of complex neurodevelopment disorders, is characterized by impaired non-verbal and verbal communication, repetitive or restricted behavior and impaired social interaction. The onset of symptoms is typically in early childhood.
Autism is very complex and no two people will exhibit or experience the same symptoms and the severity of the condition will also vary.
Nearly 1 in every 68 children have autism, boys are 4.5 times more likely to develop the condition than girls, according to the Centers for Disease Control and Prevention (CDC).
The CDC estimates costs to range anywhere from $11.5 billion and $60.9 billion for children with autism, based on 2011 calculations.
Medical experts believe autism is connected to a combination of environmental and genetic factors such as complications in pregnancy, viral infections and pollution.
In previous studies researchers discovered a link between autism and infection during pregnancy. It has been suggested that neurodevelopment may be affected by the mother’s immune response.
In other studies, researchers have discovered higher levels of inflammatory cytokines in samples of the mother’s blood and amniotic fluid. Cytokines are molecules that are released by immune cells during inflammation.
The authors note: “Maternal responses to infection, therefor, including the timing of fever episodes relative to fetal brain development and measures to mitigate fever, may influence risk of ASD.”
The research team believes their study is the most powerful of its kind to date. The researchers assessed the connection between autism and maternal fever throughout the entire pregnancy.
Data of 95,754 children born in Norway between 1999 and 2009 was examined, which included questionnaires completed by the mothers throughout their pregnancies.
The researchers identified a total of 583 cases of autism and 15,701 mothers or 16 percent who reported fever at least once during their pregnancy.
Fever was connected to a 34 percent higher risk of autism and 40 percent higher risk, when the mother self-reported fever during the second trimester of pregnancy.
The researchers analyzed to what extent ibuprofen or acetaminophen affected the correlation between fever during pregnancy and increased risk of autism.
The research team discovered an insignificant effect of acetaminophen in the second trimester. It was also discovered that none of the children who were born to the mothers that utilized ibuprofen during the second trimester developed autism.
The authors noted since the numbers were so low that it was difficult to say anything definite about how ibuprofen affected the risk of autism.
“Our results suggest a role for gestational maternal infection and innate immune responses to infection in the onset of at least some cases of autism spectrum disorder,” said leading author Mady Hornig, an associate professor at Mailman School of Public Health.
The study was published in the journal Molecular Psychiatry.