Nearly half a million Americans who suffer from autism may have a better understanding of what causes the disease, thanks to researchers at the Ohio State University Medical Center.
Dr. David Beversdorf, a neurologist from the medical center, reported on a study which shows women who are exposed to a major stressful event midway through their pregnancy may be at greater risk of having an autistic child than their other more mildly-stressed counterparts.
Genetics has always been thought to be a major contributing factor to the development of autism, but there are certain aspects of the disease which cannot be explained by genetics, Beversdorf said.
“There have been cases in the past of identical twins being born, where one shows signs of autism and one does not,” Beversdorf said. “There needs to be another variable to explain such findings.”
To test their theory, Beversdorf and his colleagues distributed surveys to specialized schools and clinics in Massachusetts and New Hampshire. Of the nearly 500 respondents, 188 women had delivered autistic children, 92 had children born with Down’s syndrome, and 212 had normal deliveries.
The researchers then asked the mothers to report their stress levels in four week blocks during their pregnancies, and then used a standard psychological measure, The Social Readjustment Rating Scale, to gauge their responses. On the scale, potentially stressful situations are assigned point values, with major stressors, such as the death of a spouse or a divorce, receiving the highest point values.
“A mother is more likely to remember stressful events during her pregnancy if she has had an autistic child,” Beversdorf said.
As the researchers had expected, the study showed women who had delivered autistic children were more likely to have experienced a major stressor between weeks 24 and 28 of the pregnancy. On average, those participants who had autistic children experienced twice as much stress as those who had normal births or bore children with Down’s syndrome.
This is consistent with earlier studies done on animals, which found stress during pregnancy may cause permanent changes to the animal’s brain structure and result in an autistic type of condition.
“In studies done with animals, if inescapable stress is applied to the mother, it will affect the pup, and the condition will last through adulthood,” Beversdorf said.
Despite the strong correlation, Beversdorf is quick to caution that a response bias may have contributed to the findings.
According to the Autism Society of America, autism is defined as a “complex developmental disability that typically appears during the first three years of life.” The disease impacts normal brain development in the areas of social interaction and communication skills.
Those afflicted with the disease typically have difficulty in verbal and non-verbal communication and social interactions, and in some cases may exhibit aggressive and/or self-injurious behavior. There are multiple types of autism, and according to a recent survey conducted by the Autism Society, as many as one in 500 people are affected by the disease.
If a woman becomes pregnant and is under a large amount of stress, Beversdorf recommended stress relievers such as counseling or enrolling in a stress management class. Beversdorf said the next step in the study will be to further work with attempts to manipulate autistic behaviors in animals, which can then be applied to humans.
