Management of hyperthyroidism during pregnancy and lactation

Abstract

Introduction: Poorly treated or untreated maternal overt hyperthyroidism may affect pregnancy outcome. Fetal and neonatal hypo- or hyper-thyroidism and neonatal central hypothyroidism may complicate health issues during intrauterine and neonatal periods. Aim: To review articles related to appropriate management of hyperthyroidism during pregnancy and lactation. Methods: Aliterature reviewwas performedusingMEDLINEwith the terms 'hyperthyroidism andpregnancy', 'antithyroid drugs and pregnancy', 'radioiodine and pregnancy', 'hyperthyroidism and lactation', and 'antithyroid drugs and lactation', both separately and in conjunction with the terms 'fetus' and 'maternal.' Results: Antithyroid drugs are themain therapy formaternal hyperthyroidism. Bothmethimazole (MMI) and propylthiouracil (PTU) may be used during pregnancy; however, PTU is preferred in the first trimester and should be replaced byMMIafter this trimester.Choanal and esophageal atresia of fetus inMMI-treated and maternal hepatotoxicity in PTU-treated pregnancies are of utmost concern. Maintaining free thyroxine concentration in the upper one-third of each trimester-specific reference interval denotes success of therapy. MMI is the mainstay of the treatment of post partum hyperthyroidism, in particular during lactation. Conclusion: Management of hyperthyroidism during pregnancy and lactation requires special considerations and should be carefully implemented to avoid any adverse effects on the mother, fetus, and neonate. © 2011 European Society of Endocrinology.