Infection during pregnancy could affect the unborn child’s risk of autism and depression as they get older, study shows.
The study was incredibly comprehensive, looking at almost 1.8 children over the course of 41 years. Researchers divided the types of infection into three categories: severe infections, like sepsis, flu, pneumonia, meningitis, or encephalitis; mild infections, like a UTI; or any infection at all.
The researchers went into the study assuming that mild infections wouldn’t increase the risk for psychiatric disorders.
They were wrong.
“From our results, it looks like we see similarly increased risk whether the mother had a UTI or something more severe,” said lead author Benjamin al-Haddad, MD. “It doesn’t seem to matter what kind of infection it is.”
The study was published on March 6, 2019, in the journal JAMA Psychiatry.
Researchers analyzed data from 1,791,520 children in Sweden whose mothers were hospitalized (while pregnant) between 1973 and 2014. Using hospital codes, they deciphered which babies had been exposed to infection in utero and then studied the children’s medical records as they grew up.
Their findings revealed that even a minor infection was linked to an increase in risk for certain psychiatric disorders. But while there was an increase in risk for depression, autism, and even suicide, there wasn’t any increased risk of other mental conditions like bipolar disorder, schizophrenia, or psychosis.
Infants who were exposed to infection during their mother’s pregnancy had a 79% increased risk of autism and a 24% increased risk of depression. They also had an increased risk of suicide, which lent even more significance to the depression risk.
But why does infection affect risk?
Researchers theorize that an infection can trigger small brain injuries in the fetus that “contribute” to the development of disorders like autism.
“We need more research into understanding the inflammation that occurs in the urinary tract infection and how it might impact the fetus,” said Dr. Kristina Adams Waldorf, professor of obstetrics and gynecology at the University of Washington School of Medicine and co-author of the study.
There also needs to be more research into the fetal brain, especially areas we already know are vulnerable to some infections, like the hippocampus, which is involved in social and emotional function.
“This could help explain how infection and inflammation during pregnancy increase the child’s risk of autism, in which social interaction is affected, and the risk of emotional disorders, such as depression,” she said in a press release.
The increased risk is in addition to the baseline risk of autism, al-Haddad stressed, and shouldn’t be cause for panic. Currently in the U.S., the risk of autism is 1 in every 59 kids.
“This is just one of a myriad of causes that we think increases risk,” al-Haddad said. “This is another piece of trying to understand what the causes of autism are and how we can prevent those causes.”
Avoiding, preventing, and treating infection during pregnancy is important, Adams Waldorf added, and underscored the importance of getting the flu shot during pregnancy.
C. Dixon likes to read, sing, eat, drink, write, and other verbs. She enjoys cavorting around the country to visit loved ones and experience new places, but especially likes to be at home with her husband, son, and dog.