Abstract
It is well established that maternal hyperthyroidism has adverse effect on fetal development. Therefore it is important to treat maternal hyperthyroidism as early as possible in order to lower the risk of both mother and fetus. It is also necessary to understand the importance of the choice of antithyroid drug, timing and indication of operation, and the radiation danger of 131 l. The aim of this article is to discuss the diagnosis and treatment of hyperthyroidism of the pregnant women and its adverse effect to the fetus.