The impact of early life exposures on future neurodevelopmental outcomes has received increasing attention, with the impact of maternal thyroid dysfunction found to be a determinant of offspring cognitive ability. Fetal neurodevelopment is solely dependent on maternal thyroid hormone in the first trimester of pregnancy, and though fetal production of thyroid hormone begins during the second trimester, the developing fetus remains partially reliant on maternally supplied thyroid hormone for the remainder of the pregnancy (1).
Thyroid hormone disorders are major determinants of maternal pregnancy related complications and adverse pregnancy outcomes (2, 3). Maternal hypothyroxinemia has been found to be associated with preterm birth, low birth weight, the head growth of young child, placental abruption, cognitive delay and many other abnormal neurobehavioral development of affected offspring (4-9). Maternal hyperthyroidism is also highly associated with maternal and fetal adverse events, such as pre-eclampsia, miscarriage, stillbirth, preterm birth, intrauterine growth restriction (5). All these adverse events can in turn disrupt the development of the nervous system resulting in offspring poor neurodevelopment.
Exposures during pregnancy may also result in permanent negative health outcomes among exposed offspring and we aim to investigate the impact of maternal thyroid function on offspring’s neurobehavioral and other health outcomes in early childhood and adolescence. Several studies reported that both maternal and neonatal thyroid function status affects the neurophysiology of the offspring prior to adolescence. However, there is a dearth of information regarding its effect on behavioural and psychiatric disorders.
The aim this study is to investigate whether abnormal maternal thyroid hormone levels affect i) the thyroid function of offspring, ii) neurobehavioral development in early childhood and adolescence, iii) offspring’s body size status during delivery, and iv) investigating the effect on late adolescents behavioural and psychiatric disorders.

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