<h3>To the Editor.</h3> —Spontaneous remission of hyperthyroidism and hypothyroidism following pregnancy has been associated with elevated levels of thyroid antimicrosomal antibodies during the time of altered thyroid function.<sup>1.2</sup>A woman with transient hyperthyroidism during pregnancy was noted to have elevated thyroidstimulating immunoglobulin levels only when she was hyperthyroid, but negative antimicrosomal antibodies throughout her course. <h3>Report of a Case.</h3> — A 25-year-old woman was seen when she was three months pregnant. She had symptoms and signs of hyperthyroidism and a 50-g goiter. Past medical history was remarkable in that during each of her preceding three pregnancies she had noted a goiter and similar symptoms, all of which resolved after delivery. A suppression test with liothyronine sodium (Cytomel) resulted in an increase in serum thyroxine level from 15.6 to 19.5 μg/dL. She was given propranolol hydrochloride, 10 mg four times daily; this was continued until delivery of a normal infant