Answer:
Helping the client change her position
Explanation:
Based on the information provided within the question it can be said that the most beneficial nursing action at this time would be to help the client change her position. This is because the main task required of the patient is to change to the supine position, but the patient may not know what that position is or may not be able to do so due to her pregnancy. Therefore the most useful nursing action would be to help.
