According to new findings supported by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, swelling through early pregnancy may be connected to increased autism risk in children. This was discovered by researchers in the study of children of mothers with elevated C-reactive protein (CRP), a well-established indicator of systemic inflammation.
The study found that the risk of autism among children was increased by 43 percent among mothers with CRP levels in the top 20th percentile, and by 80 percent for maternal CRP in the top 10th percentile. The findings add to increasing proof that an overactive immune reaction can change the progress of the central nervous system in the fetus.
“Elevated CRP is a signal that the body is undergoing a response to inflammation from, for example, a viral or bacterial infection,” said lead scientist on the study, Alan Brown, M.D., professor of clinical psychiatry and epidemiology at Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, and Mailman School of Public Health. “The higher the level of CRP in the mother, the greater the risk of autism in the child.”
Brown cautioned that the results should be viewed in perspective since 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.”
“The brain develops rapidly throughout pregnancy,” said Linda Birnbaum, Ph.D., director of NIEHS, which funds a broad portfolio of autism and neurodevelopmental-related research. “This has important implications for understanding how the environment and our genes interact to cause autism and other neurodevelopmental disorders.”
The study appears in the journal Molecular Psychiatry and capitalizes on a unique national birth group known as the Finnish Maternity Cohort (FMC), which contains a collection of samples collected from pregnant women in Finland. Finland also maintains diagnoses of nearly all childhood autism cases from national registries of both hospital admissions and outpatient treatment.
“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., head of the NIEHS Cellular, Organ, and Systems Pathobiology Branch and 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.”