Final answer:
An increase in the pulse rate from 88 to 102 beats per minute would be an early sign of excessive blood loss in the immediate postpartum period.
Step-by-step explanation:
The nurse should monitor the client in the immediate postpartum period for signs of hemorrhage. An early sign of excessive blood loss in this situation would be an increase in the pulse rate from 88 to 102 beats per minute. This can indicate the body's compensatory response to a decrease in blood volume, as the heart pumps faster to maintain blood flow.