ABSTRACT
The pregnancy of a women with diabetes mellitus was complicated by Graves' disease and maternal allergies to propylthiouracil and methimazole. Preparations for surgical removal of the thyroid gland were being made until pregnancy intervened. Several well-documented mechanisms of hyperthyroidism, including increased intestinal absorption of glucose, decreased insulin responsiveness, and increased glucose production may exacerbate glucose intolerance; the daily insulin requirement of this patient rose 80% from her pregestational dosage. When large doses of propranolol failed to control her thyrotoxic symptoms and led to severe, recurrent hypoglycemic episodes, subtotal thyroidectomy was performed. A 42% decrease in insulin requirements was observed postoperatively, with return to the euthyroid state. A propensity for symptomatic postoperative hypoglycemia should be anticipated in diabetic patients undergoing thyroidectomy.
