Fever During Pregnancy Increases Risk of Autism
Fever is part of the body’s defense system against infection such as bronchitis or flu and is beneficial because it helps kill the bacteria and other organisms that cause infections. But women who have fever during pregnancy face a significant downside, as a new study shows they are more likely to have a child with autism or developmental delay.
Fever during pregnancy can be serious
Fever is a temporary increase in the body’s temperature and is produced by acute inflammation in response to an illness, disease, or an environmental situation, such as high humidity, heavy exercise, or use of some medications. A fever in an adult is defined as a body temperature greater than 99.0 to 99.5 degrees F, depending on the time of day.
Generally, adults who experience mild fever do not need any treatment other than staying hydrated and resting. However, investigators at the University of California (UC) Davis, have uncovered “strong evidence” regarding fever in pregnant women that deserves immediate attention.
According to Ousseny Zerbo, the study’s lead author and a PhD candidate with UC Davis at the time of the study, “We recommend that pregnant women who develop fever take anti-pyretic medications and seek medical attention if their fever persists.”
The reason for this advice is that the researchers discovered that women who experienced fever during pregnancy were more than twice as likely to give birth to a child with autism or developmental delays than were women who did not have a fever or who took medications to fight it.
These findings are based on data analyzed from the Childhood Autism Risk from Genetics and the Environment (CHARGE) Study. CHARGE included an ethnically diverse group of children aged 2 to 5 years born and living in California.
This latest study from UC Davis involved 538 children with autism, 163 children with developmental delay but without autism, and 421 typically developing children. The mothers of all the children responded to questions about whether they had experienced the flu and/or fever while they were pregnant and if they treated their illnesses with medications.
Based on the responses, the authors noted the following:
- Having the flu during pregnancy was not associated with an increased risk of having a child with autism or developmental delay
- Fever associated with any cause during pregnancy was more likely to be reported by women who had children with autism (2.12 times higher odds) or developmental delay (2.5 times higher odds) when compared to women with children who were developing typically
- The risk of autism among children of women who treated their fever with anti-fever medications during pregnancy was the same as the risk in children whose mothers said they had not experienced fever
Previous findings regarding pregnancy and autism
CHARGE was also the basis for earlier research which reported that women who were obese or who had diabetes were more likely to give birth to children with autism. Irva Hertz-Picciotto, professor of public health sciences at UC Davis and the principal investigator of CHARGE, pointed out that “Since an inflammatory state in the body accompanies obesity and diabetes as well as fever, the natural question is: Could inflammatory factors play a role in autism?”
This is an intriguing question, and one that Hertz-Picciotto believes deserves consideration. She noted that “We definitely think more research is necessary to pinpoint the ways that inflammation could alter brain development.”
The latest study from UC Davis is believed to be the first to examine fever during pregnancy as having a role in autism or developmental delay. Other studies based on CHARGE data have shown that women who take prenatal vitamins before and during their first month of pregnancy may help prevent autism and that pregnant women who live in areas with high air pollution have a higher risk of giving birth to a child with autism.
Although this study does not definitively state that having a fever during pregnancy can increase the risk of giving birth to a child with autism, it does raise the possibility. The study results also provide potential parents and physicians with important information to consider if a woman develops a fever during pregnancy.
Krakowiak P et al. Maternal metabolic conditions and risk for autism and other neurodevelopmental disorders. Pediatrics 2012; doi:10.1542/peds.2011-2583
University of California, Davis
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