Thyroid and Pregnancy

Pregnancy is associated with an increased requirement of hormone secretion by the thyroid, within the first weeks after conception. To this greater demand to occurs, pregnancy induces a series of physiological changes that affect thyroid function and, consequently, the tests of glandular function. For normal pregnant women living in areas with a sufficient supply of iodine, this challenge regarding the adjustment of thyroid hormone releases to this new state of equilibrium and its maintenance until the end of pregnancy it meets no difficulties. However, among women with impaired thyroid function due to some thyroid disease or among women residing in areas with an insufficient iodine supply, this does not occur. The management of thyroid dysfunction during gestation requires special considerations, since both hypothyroidism and hyperthyroidism can lead to maternal and fetal complications. In addition, thyroid nodules are detected at reasonable frequency among pregnant women, a fact that requires a differential diagnosis between benign and malignant growths during the pregnancy itself. (Arq Bras Endocrinol Metab 2008; 52/7:1084-1095)