A patient is in the immediate postpartum period after having delivered 9 pound. 14-ounce baby (4480 grams). iS 6. The patient is gravida 6, para 5. The nurse notices some new blood stains on the top sheets and discovers the patient lying in a pool of blood. The fundus is located above the umbilicus and is boggy. The bladder is not palpable. What would be the nurse's priority action?