The interpretation of thyroid tests and the diagnosis of thyroid pathology may be a challenge for the physician caring for pregnant women. In the last decade, improvements in the sensitivity of thyroid tests, such as serum thyrotropin (TSH), have clarified some issues related to thyroid physiology in the pregnant state. <sup>22 Glinoer D. The regulation of thyroid function in pregnancy: Pathways of endocrine adaptation from physiology to pathology Endocr Rev 1997 ;  18 : 404  [cross-ref]

Cliquez ici pour aller à la section Références</sup> Although autoimmunity has traditionally been considered to be the most common etiology of disorders of the thyroid gland affecting pregnant women, new studies indicate that hyperthyroidism caused by the inappropriate production of human chorionic gonadotropin (hCG) is the leading cause of abnormalities in thyroid tests during the first half of pregnancy. <sup>23 Goodwin T.M., Montoro M.N., Mestman J.H. , et al. The role of chorionic gonadotropin in transient hyperthyroidism of hyperemesis gravidarum J Clin Endocrinol Metab 1992 ;  75 : 1333-1337  [cross-ref]

Cliquez ici pour aller à la section Références</sup> However, from a clinical point of view, hyperthyroidism owing to Graves' disease remains the most important cause of maternal and fetal morbidity. <sup>47 Mestman J.H. Hyperthyroidism in pregnancy Clin Obstet Gynecol 1997 ;  39 : 45-64  [cross-ref]

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Hyperthyroidism is second to diabetes mellitus as the most common endocrine disorder seen in pregnancy. Women with active or treated hyperthyroidism need to be advised concerning the potential medical problems that they and their fetuses may encounter during gestation, particularly if thyroid dysfunction is not managed properly. The outcome of pregnancy may be affected not only in women with active hyperthyroidism but in some patients with Graves' disease who have previously been treated with ablation therapy, involving either surgery or radioactive iodide (RAI). A team approach to management is strongly recommended, with the participation of an endocrinologist, obstetrician, perinatologist, neonatologist, and anesthesiologist. This article reviews the prevalence and etiology of hyperthyroidism in pregnancy; hyperthyroidism caused by the inappropriate secretion of hCG; potential maternal, fetal, and neonatal morbidity in hyperthyroidism associated with Graves' disease; management of hyperthyroidism during gestation; prepregnancy counseling; issues related to breast-feeding in mothers taking antithyroid drugs (ATD); and postpartum thyroid dysfunction in patients with Graves' disease.