A multiparous woman is admitted to the postpartum unit after…

A multiparous woman is admitted to the postpartum unit after a rapid labor and birth of a 4000-g infant. Her fundus is boggy, lochia is heavy, and vital signs are stable and unchanged. The nurse has the woman void and massages her fundus, but the fundus remains difficult to find, and the rubra lochia remains heavy. Which action would the nurse take next?