TSHR and hyperthyroidism: The determination of TSH receptor antibodies (TSHRAb) or thyroid stimulating immunoglobulins (TSI) is indicated in mothers in whom previous pregnancies have been complicated by fetal or neonatal hyperthyroidism, in mothers with active disease on antithyroid drug therapy, in mothers with thyroidectomy during pregnancy, in mothers with a previous history of ablation therapy for Graves' hyperthyroidism, and in the presence of fetal tachycardia and incidental fetal goiter on ultrasonography.