Children whose mothers experienced any type of infection during pregnancy were nearly 80 times more likely to be diagnosed with autism than those whose mothers did not have infections, based on data from more than one million children in Sweden.
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Although previous studies have shown associations between specific infections in utero and specific conditions, such as schizophrenia, “Whether maternal infection and inflammation can alter fetal neurodevelopment to a degree that imparts risk for a broad spectrum of psychopathologic conditions across the child’s lifetime is unknown,” wrote Benjamin J. S. al-Haddad, MD, formerly of Seattle Children’s Hospital, Washington, currently with Doctors without Borders,Katiola, Côte d’Ivoire, and his colleagues.
In a study published In JAMA Psychiatry, the researchers followed 1,791,520 children (48.6% girls) born between Jan. 1, 1973, and Dec. 31, 2014, for up to 41 years using population-based registry data.
Overall, researchers found a 79% increased risk of an autism diagnosis (hazard ratio 1.79) and a 24% increased risk of a depression diagnosis (HR 1.24) for individuals exposed to any maternal infection in utero compared with those not exposed.
Similar increases in risk appeared when the data were broken down by type of infection. Hazard ratios for an autism diagnosis were 1.81 for exposure to a severe maternal infection and 1.89 for a maternal urinary tract infection; hazard ratios for depression were 1.24 and 1.30, respectively, for severe maternal infection and maternal urinary tract infection.
No increased risk in bipolar disorder, or other psychoses including schizophrenia were observed.
The findings were limited by several factors including the inclusion only of infections diagnosed in a hospital setting, and thus may not be generalizable to infections diagnosed in an outpatient setting, the researchers noted. However, the results “amplify the urgency to better understand the role of maternal infection during pregnancy on fetal brain development and suggest that prevention of infection (such as by influenza vaccination) or anti-inflammatory therapies may be important strategies for the primary prevention of some portion of autism and depression,” they said.
The researchers had no conflicts to disclose. The study was funded by grants from several organizations including the National Institutes of Health.
SOURCE: al-Haddad BJS et al. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2019.0029.