Final answer:
Providing a warm blanket for comfort is an appropriate nursing measure when performing a postpartum check on a 40-year-old client.
Step-by-step explanation:
When performing a postpartum check on a 40-year-old client, a nursing measure that would be appropriate is providing a warm blanket for comfort. This can help the client feel more relaxed and at ease after giving birth. Additionally, it is important to ensure that the client is kept warm to prevent hypothermia, as the body temperature may drop slightly after delivery.