Final answer:
The priority assessment for a nurse caring for a client in the fourth stage of labor and receiving oxytocin is the amount of vaginal bleeding to quickly identify and manage potential postpartum hemorrhage.
Step-by-step explanation:
The student asked which assessment is the nurse's priority for a client in the fourth stage of labor and receiving oxytocin via continuous IV infusion. Priority should be given to assessing the amount of vaginal bleeding. This is because after the delivery of the placenta, the fourth stage of labor, also known as the recovery stage, includes close monitoring for hemorrhage. Postpartum hemorrhage is one of the leading causes of maternal mortality, and excessive vaginal bleeding can be a vital sign of this life-threatening condition. Other assessments such as urinary output, pain level, and fundal height are also important but secondary to the immediate identification and management of hemorrhage.