Iodine is a crucial component of thyroid hormones (THs), specifically triiodothyronine (T3) and thyroxine (T4) and is vital for normal thyroid function. During pregnancy, a deficiency in iodine can result in inadequate production of THs, leading to hypothyroidism. This con-dition can negatively impact the intellectual development of the newborn. Numerous stud-ies have demonstrated that iodine deficiency during pregnancy correlates with lower IQ levels in children. This deficiency can hinder critical processes such as neurogenesis, neu-ronal migration, and myelination, all of which are essential for proper cognitive develop-ment. Research indicates that children born to iodine-deficient mothers are at a higher risk of having lower IQs compared to those whose mothers received iodine supplements during pregnancy. Therefore, ensuring sufficient iodine levels and optimal TH function during pregnancy is crucial for the cognitive development of children. This highlights the im-portance of nutrition and regular monitoring of thyroid health in pregnant women. This re-view focuses on the key mechanisms of thyroid hormone homeostasis and discusses the implications of iodine deficiency during pregnancy.