Abstract
Graves' disease in pregnancy may be associated with maternal, fetal and neonatal complications, which are proportionate to the severity of hyperthyroidism. Optimal management is detailed preconception counselling, achievement of an euthyroid state prior to conception, and close monitoring of thyroid function and thyroid-stimulating antibodies together with judicious use of anti-thyroid medications during pregnancy. A case of Graves' disease in pregnancy, complicated by pancytopenia, with a deterioration in thyroid function following cessation of thionamide therapy is described here. Therapeutic plasma exchange was subsequently used to achieve rapid control prior to thyroidectomy. Therapeutic plasma exchange is an effective treatment for hyperthyroidism where thionamides are ineffective or contraindicated, as a bridge to definitive management.