The literature on the use of thiouracil drugs in the treatment of hyperthyroidism complicated by pregnancy is scant and in most instances is confined to reports of one or two cases. My experiences and those of associates at the Lahey Clinic with 21 such cases are, therefore, being reported with the hope of partly filling in this gap in our knowledge.
Since the introduction of thiouracil in 1943, this drug or its derivatives have been used at the clinic in the preoperative preparation of over 1,900 thyrotoxic patients. There were 21 women whose hyperthyroidism was complicated by pregnancy. Three patients had recurrent hyperthyroidism, and 18 had primary hyperthyroidism. Subtotal thyroidectomy was performed on each patient during the course of the pregnancy after she had been prepared with one of the thiouracil drugs and strong iodine (Lugol's) solution. The duration of hyperthyroidism ranged from two months to four years. The duration