Could IVF be linked to autism?

According to research by Dr Ditza Zachor of Tel Aviv University's Sackler School of Medicine, 10.5% of 461 children at the Autism Center at the Assaf Harofeh Medical Center in Israel which Dr. Zachor directs, who had been diagnosed with a disorder on the autism spectrum, were conceived using IVF, a significantly higher number than the 3.5% autism rate in the general Israeli population.

Dr Zachor notes that mothers in her study who had IVF tended to be older - with a median age of 32.6 years. Also significantly, nearly 4% of the children with autism were born prematurely, and about 5% of those had a low birth weight. In the general population, only about 1% of all newborns are delivered with a low birth weight.

Dr Zachor says that it is too early to make a serious deduction based on this evidence alone and her ongoing research will attempt to separate out risk factors and come up with more precise numbers for autism and other prenatal conditions in IVF.

The key may be "imprinting," a biochemical procedure during cell division which determines which genes will be selected or "expressed" in the embryo. Research into epigenetics - changes in gene expression that occur without a change in the DNA sequence - suggest that the malformations may be caused by imprinting abnormalities introduced into the embryo while it's in a test tube environment.

However, Dr Zachor does not want to discourage infertile couples from undergoing IVF implantation, which most often results in a healthy child; : the majority of children born using IVF do not have autism, and most children who have autism were not conceived using IVF.

Courtesy of Science Daily

First published in July 2010

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