While hyperthyroidism is relatively uncommon in pregnancy, Graves’ disease is the leading cause when it does occur. The prevalence of Graves’ disease in the general population is around 0.5%, with hyperthyroidism affecting between 0.1% and 0.4% of pregnant women. Graves' disease is more frequent in women of reproductive age, typically between the ages of 20 and 40. Other causes of hyperthyroidism, such as toxic multinodular goiter and autonomous thyroid nodules, are less common in women under 40.
Pregnancy can both exacerbate and mask the symptoms of hyperthyroidism, making diagnosis more challenging. Additionally, the physiological changes during pregnancy, such as increased TBG levels and hCG's effect on the thyroid, can complicate the interpretation of thyroid function tests. In regions where iodine deficiency is prevalent, the risk of thyroid dysfunction, including hyperthyroidism, may be higher due to the development of functional thyroid nodules. Thus, careful monitoring of thyroid function is crucial for pregnant women at risk of thyroid disorders.
