Fetal Thyrotoxicosis due to Maternal TSH Receptor Stimulating Antibodies Causes Infant Central Hypothyroidism

Abstract

<b><i>Introduction:</i></b> Women with a current diagnosis or past history of Graves’ disease (GD) are at risk of developing fetal thyrotoxicosis (FT) during pregnancy when they are inadequately treated, or because of placental passage of TSH receptor antibodies (TRAb). It is known that FT induced by high <i>maternal</i> thyroid hormone concentrations may result in infant (central) hypothyroidism. <b><i>Case Presentation:</i></b> In a euthyroid woman with a history of GD treated with radioactive iodide (I¹³¹), persistently high levels of maternal TRAb resulted in recurrent FT during two separate pregnancies, followed by neonatal hyperthyroidism and infant central hypothyroidism. <b><i>Discussion:</i></b> This case demonstrates the novel insight that FT due to high <i>fetal</i> thyroid hormone concentrations stimulated by high maternal TRAb levels might also result in (central) hypothyroidism, requiring long-term evaluation of the hypothalamus-pituitary-thyroid axis in these children.