In order to arrive at this conclusion, researchers at Houston Methodist Neurological Institute and Erasmus Medical Centre analyzed 4,039 Dutch mothers and their children.
These mothers voluntarily registered between 2002 and 2006 for the ‘Generation R Study’. Of these 59 mothers were highly T4 deficient, while 136 of them were identified as mildly T4 deficient. In all 80 “probable autistic children” were identified by the study researchers.
For the purpose of the study, a woman having less than 5 percent of normal T4, but producing a normal amount of thyroid stimulating hormone was termed as highly T4 deficient.
The blood samples of the study participants was taken in the 13th week of pregnancy to measure levels of T4 as well as of two other proteins that tend to point towards the cause of iodine deficiency>.
T4 Deficiency Leads to Symptoms
The study established that in cases where women were severely T4 deficient, the autistic symptoms were more pronounced in children. Likewise, mild deficiency of T4 in mothers resulted in an inconsequential quantum of increase in autistic children’s symptoms.
Lack of Iodine in diet is stated to be the most common cause of thyroid hormone deficiency.
The findings of the latest study corroborate with earlier findings that suggest foetal brain cells migrate during the process of embryo development.
“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,” said lead author Gustavo Roman, a neurologist and neuroepidemiologist.
The findings of the study suggest that pregnant women should routinely measure their urinary iodine levels as well as thyroid hormone levels.
The study will be published in the journal Annals of Neurology.