The Houston Methodist Neurological Institute and the Erasmus Medical Centre will be publishing their results in an upcoming Annals of Neurology regarding the connection they have found between a mother’s thyroid function and autism.

The study found that mothers with severe thyroid dysfunction (in the form of a severe T4 deficiency) were found almost four times more likely to have an autistic child. They also found a mild connection to those with moderate thyroid issues. This information builds on past studies which have shown that maternal thyroid hormones are crucial to the migration of fetal brain cells during embryo development.

According to the lead author of the study, Gustavo Román, M.D., a neurologist and neuroepidemiologist who directs the Nantz National Alzheimer Center, “It is increasingly apparent to us that autism is caused by environmental factors in most cases, not by genetics. That gives me hope that prevention is possible."

His advice to mothers? "If you are planning to become pregnant, have your doctor measure urine iodine and thyroid function beforehand. If you have just become pregnant, have your doctor measure urine iodine, thyroid function, and begin using prenatal vitamins, making sure iodine is present."

Why the focus on iodine?  Iodine is well researched and found to be connected not only to normal thyroid function, but a lack of it during pregnancy can lead to complications such as deafness and developmental delay in the baby, and loss of control of fat and sugar metabolism and heat generation in the mother.

In a 2007 review, Román published in the Journal of Neurological Sciences evidence that the near-epidemic rise in autism diagnoses could be partially caused by iodine-starved diets (which disrupt thyroid function) and/or exposures to toxins.

The next step for the team is doing interventional studies; where those tested with low thyroid function in early pregnancy, have thyroid function corrected. If women treated are found to have smaller numbers of autistic children, then Román’s theory will bear even more weight. 

For more information on the study, go here. 

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