Autism:  Predictive effect of low-thyroid function during the first trimester of gestation

The increasing incidence of Autism Spectrum Disorders (ASD) in the USA and Europe suggests a causal environmental factor.  Neuropathological brain changes in autism are consistent with an alteration of neuronal cortical migration occurring early in gestation (gestational age, GA 8-12 weeks).  Maternal thyroid hormones are critical for neuronal migration.  Thyroid function depends on appropriate iodine content in the diet; also, numerous environmental factors affect thyroid function.  A large number of anti-thyroid compounds are present in many natural and man-made products.  Based on clinical and experimental evidence, Dr. Román postulated that maternal hypothyroxinemia (low T4) during the first trimester (GA 8-12 weeks) may adversely affect neuronal migration leading to abnormal cortical formation of brain and cerebellum, resulting in autism.

This research project aimed to test the hypothesis that abnormal function tests during pregnancy predict autism by performing appropriate statistical analyses using de-identified data contained in the database from a cohort of mothers and their children [The Generation R Study] in Rotterdam, The Netherlands. It was expected that the incidence of ASD would be significantly higher in the group of cases with early maternal hypothyroxinemia compared to normal controls.