Perspective on Maternal Obesity & Autism

April 13, 2012

 Today’s “Got Questions?” answer is from Alycia Halladay, Ph.D., former Autism Speaks director for environmental research.

I’m hearing about a new link between a mom’s obesity and autism. What does it mean?

This past week, the journal Pediatrics published a study that shows an association between maternal obesity and autism spectrum disorder (ASD). It also links type 2 diabetes and gestational (pregnancy-related) diabetes with ASD. These maternal health conditions are associated with increased autism risk in some people, but are not necessarily causative. In other words, these factors slightly increase the risk for autism in some people, but do not directly cause it.  Further, the researchers suggest that the increased risk is likely due to an underlying metabolic condition – such as insulin resistance – which is associated with obesity and diabetes. More research is needed to better understand how a mother’s insulin resistance can affect a child’s prenatal development.

Other studies have provided additional information relating prenatal health and autism risk. Taking prenatal vitamins before becoming pregnant, for example, can reduce the risk of autism. Close spacing of pregnancies is associated with increased autism risk, as are maternal infection during pregnancy and premature birth. These factors influence brain development during the prenatal period. They increase risk not only for autism, but also other neurodevelopmental disorders and delays.

Advanced parental age is yet another known risk factor for autism, especially that of the father. Like maternal obesity, these factors modestly increase the risk for autism. If several of these factors coincide – and the child has underlying genetic susceptibility to autism – the chances that the will develop autism become higher.

Scientists consider all of these influences to be “environmental” risk factors for autism, to distinguish them from genetic factors. It’s important to understand that no one of these environmental influences causes autism in and of itself. Rather they appear to increase or decrease the relative risk of autism – at least in those who are genetically predisposed to ASD.

This week’s Pediatrics article is one in a number of reports that have come out of the Childhood Autism Risks from Genetics and the Environment Study (CHARGE)over the past few years. They provide evidence that compromised maternal health during pregnancy – and even prior to pregnancy – can increase the risk that a child will develop autism.  Research likewise shows that compromised maternal health is a risk factor for other health conditions. These research findings have been emerging for years, and we’re sure to see more of them. We want people to be aware of them without becoming overwhelmed by them.

Therefore, the most compelling guidance to women who are pregnant or thinking of becoming pregnant is to be as healthy as you can be. Seek and follow the guidance of your obstetrician or other healthcare provider before you become pregnant and through your pregnancy.

Autism Speaks continues to actively fund research on environmental factors and gene-environment interactions and how they influence the risk of autism. You can explore these and other studies using the Autism Speaks Grant Search. This research is made possible by the inspiring dedication and efforts of our families, volunteers and donors. Thank you so much for your support, and please keep sending us your questions at

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