ANNAPOLIS, MD. (FRONTLINE MEDICAL NEWS) – Febrile infections occurring in the second trimester appear to pose the greatest risk to the neurodevelopment of the fetus, a population based cohort study has shown.

In a review of 8,618,171 California births between January 1991 and December 2008, Ms. Hilary Haber, a third-year medical student at the University of California, Davis, and her coinvestigators found that maternal infections requiring hospitalizations during the second trimester were associated with a relative risk of 2.5 of having a child with epilepsy, a relative risk of 2.3 of having a child with an intellectual disability, and a relative risk of 1.2 of having a child with autism.

Significant associations were observed between subcategories of infection and intellectual disability and epilepsy, particularly those of a bacterial cause and from respiratory and genitourinary sites. Overall, any maternal infection during pregnancy was associated with a 43% increased risk of epilepsy, a 33% increased risk of intellectual disability, and an 8% increased risk of autism.

The exact mechanism of action between the maternal infection and adverse fetal neurodevelopmental outcomes is still unclear, Ms. Haber said at the annual scientific meeting of the Infectious Diseases Society for Obstetrics and Gynecology.

“Next, we are considering which specific [maternal] infections we should look at,” Ms. Haber said in an interview. “There is something about febrile infections, so we want to narrow that down and better characterize the outcomes from mild, moderate, severe infections.”

Ms. Haber reported having no relevant financial disclosures.

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