Maternal inflammation during early pregnancy has been linked to an increased risk of autism in children, according to new research.
In the new study, researchers found an increased risk of autism in children of mothers with elevated C-reactive protein (CRP), a marker of systemic inflammation.
Researchers note there is mounting evidence that an overactive immune system can alter the development of the central nervous system in a fetus.
The study found that the risk of autism was increased by 43 percent for children whose mothers had CRP levels in the top 20th percentile, and by 80 percent for maternal CRP in the top 10th percentile.
“Elevated CRP is a signal that the body is undergoing a response to inflammation from, for example, a viral or bacterial infection,” said Alan Brown, M.D., professor of clinical psychiatry and epidemiology at Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute.
“The higher the level of CRP in the mother, the greater the risk of autism in the child.”
The findings should be kept in perspective, Brown cautioned, noting that the prevalence of inflammation during pregnancy is “substantially higher” than the prevalence of autism.
“The vast majority of mothers with increased CRP levels will not give birth to children with autism,” Brown said. “We don’t know enough yet to suggest routine testing of pregnant mothers for CRP for this reason alone; however, exercising precautionary measures to prevent infections during pregnancy may be of considerable value.”
For the study, researchers analyzed data collected by the Finnish Maternity Cohort, which includes 1.6 million specimens from about 810,000 pregnant women in Finland, including serum, a component of whole blood. Finland also maintains a database of virtually all childhood autism cases from national registries of both hospital admissions and outpatient treatment, the researchers noted.
The researchers analyzed CRP in maternal serum corresponding to 677 childhood autism cases and an equal number of matched controls. The work was conducted with researchers in Finland, including the University of Turku and the National Institute for Health and Welfare in Oulu and Helsinki.
“Studying autism can be challenging, because symptoms may not be apparent in children until certain brain functions, such as language, come on line,” said Cindy Lawler, Ph.D., program lead for the Institute’s extramural portfolio of autism research.
“This study is remarkable, because it uses biomarker data to give us a glimpse back to a critical time in early pregnancy.”
According to the scientists, this work is expected to stimulate further research on autism. Future studies may help define how infections, other inflammatory insults, and the body’s immune response interact with genes to elevate the risk for autism and other neurodevelopmental disorders.
The study appeared in the journal Molecular Psychiatry.
Source: National Institutes of Health