Final answer:
The nurse should closely monitor the client's blood pressure postpartum, since the recorded measurement of 148/92 mm Hg is considered high and could be indicative of complications such as preeclampsia.
Step-by-step explanation:
After giving birth, the vital sign that the nurse would continue to monitor closely is the blood pressure, as the reading of 148/92 mm Hg is elevated. Normal blood pressure typically falls between 90/60 and 120/80 mm Hg. The other vital signs are within normal ranges; pulse rate of 80 beats/min is within the normal range of 60-100 beats per minute, the temperature of 99.4°F (37.4°C) is slightly above the average but not necessarily a cause for immediate concern, and the respiratory rate of 16 breaths/min is well within the normal range of 12-18 breaths per minute. Given that high blood pressure can be a sign of complications like preeclampsia, it's imperative to continue monitoring the blood pressure closely postpartum.