Transient hypoparathyroidism with hypocalcemia occurs in up to 20 % of patients after surgery for thyroid cancer, multinodular goiter or Graves' disease and is severe in around 3 to 18% of cases. Severe hypocalcemia significantly lengthens their hospital stay. This study will evaluate the effects of teriparatide (synthetic parathyroid hormone, brand name Forteo) on low calcium levels in the setting of thyroid surgery associated with low parathyroid hormone.