Final answer:
The nurse should include preparing an ice pack for application to the area in the plan of care for a PP woman with a small vulvar hematoma.
Step-by-step explanation:
The specific intervention that the nurse should include in the plan during the first 12 hours following delivery for a PP woman with a small vulvar hematoma is D. Prepare an ice pack for application to the area. Ice packs can help reduce swelling and provide relief from pain or discomfort. It is important to monitor the hematoma for any changes in size or signs of infection. The other options mentioned in the question, assessing vital signs, informing healthcare providers of assessment findings, and measuring fundal height, may be part of the overall plan of care for the PP woman but are not specifically related to the small vulvar hematoma.