Thursday, January 13, 2011

Correlation found between Autism and timing of pregnancies

New research finds that autism is 3x more likely in children who were born less than a year after their older siblings. In other words, something about the time elapsed between pregnancies is related to the odds of having a child with autism. There is speculation that the connection between autism and inter-pregnancy-interval (IPI) might be "related to maternal depletion of key nutrients such as folate".

I am always fascinated by how much mystery and controversy surrounds autism. In this case it seems likely that something about the pre-natal time period is increasing the risk of autism. However, it seems like a good idea to point out once again that correlation is not causation (for a related thread see my discussion of baby sleep and the problem of spurious correlation). The fact that the incidence of autism increases with a shorter interval between pregnancies does not mean a shorter IPI causes autism. However, this research does raise all sorts of questions that could lead us to new knowledge about autism.

As someone who has worked with both children and adults with autism I have always felt that autism was a very complex diagnosis that is probably a result of genetic, environmental, and social processes. Unlike something like Downs' Syndrome I doubt that autism will ever be linked to a discrete gene or chromosome. Although I am happy to see research exploring possible causes or contributing factors to autism, I am wary that research which points to maternal factors as a cause may lead us down the path of blaming parents. In the early 20th century "bad mothers" were commonly seen as causing mental retardation among children (see Trent's book "Inventing the Feeble Mind" 1994), and I would hate to see us return to that type of logic even obliquely.

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