A recent study published in Molecular Psychiatry suggests that any type of fever during pregnancy can increase the risk of a child developing an autism spectrum disorder later in life.

The study’s data showed that one episode of a fever in the second trimester could increase autism risk by 40 percent. Several instances of fever after the first trimester could increase the risk threefold. Nearly 100,000 children born in Norway between 1999 and 2009 were studied. Nearly 600 of the children were diagnosed with autism spectrum disorder.

The study’s lead researcher, Dr. Mady Hornig (associate professor of epidemiology at Columbia University’s Mailman School of Public Health) stated that the risk of a child developing autism due to a fever in utero is low. For the majority of pregnant women who develop a fever during pregnancy, autism is not present in their child. In fact, fever is quite common during pregnancy and the majority of children born do not have autism.

It’s also important to note that while there may be an association, this does not mean that the fever causes autism in any instance. It is unknown what the association is between fever during pregnancy in autism, though some researchers speculate that it could involve the body’s reaction to infection and brain development. Dr. Hornig also indicated that there are likely many contributing factors to autism.