Background: During pregnancy, changes in maternal physiology influence thyroid status. In addition, maternal thyroid disease can have substantial adverse effects on the fetus. Therefore, evaluating and treating women with thyroid disease during pregnancy requires careful observation and management to ensure favorable pregnancy outcomes. To evaluate thyroid hormone levels during gestation, gestational age-specific values should be used. When hyperthyroidism is treated, the goals of therapy are to achieve a subclinical hyperthyroid state and monitor fetal development. Care must be taken so as not to induce a state of maternal hypothyroidism during pregnancy, since such a diagnosis is also associated with adverse outcomes for both mother and infant. Conclusions: Consideration should be given to routine screening of pregnant women and all women of childbearing age for thyroid disease.