A nurse is аssessing а client whо is 4 dаys pоstpartum fоllowing an uncomplicated vaginal delivery. The nurse notes the following assessment findings: Temperature: 37.2°C (99.0°F) Heart rate: 118 beats/min Blood pressure: 94/58 mm Hg Respiratory rate: 20 breaths/min Oxygen saturation: 99% on room air The client reports feeling lightheaded when standing. She states she has been changing a perineal pad every hour because "it keeps getting soaked." Lochia remains bright red with several quarter-sized clots. The client states her uterine cramping has "almost completely stopped." Which nursing action should the nurse implement FIRST?