Thyroid disorders are among the most common endocrine diseases in pregnancy. Providers will frequently be called upon to diagnose, treat, and monitor women with these conditions. Undiagnosed or uncontrolled thyroid conditions may lead to perinatal morbidity and even mortality. Both thyrotoxicosis and hypothyroidism are associated with adverse pregnancy outcomes. There also is concern about the effect of overt maternal thyroid disease on fetal development. In addition, medications that affect the maternal thyroid gland can cross the placenta and affect the fetal thyroid gland. The association between subclinical hypothyroidism and pregnancy complications is less clear. Treatment for overt hypothyroidism with thyroid replacement is universally recommended, which decreases risks of complications. Despite the morbidity of thyroid disorders, there is no clear evidence for the benefit of universal screening in pregnancy. 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 [1].