Which nursing intervention should be implemented before performing Leopold's maneuvers?

Having the client empty her bladder is the appropriate nursing intervention before performing Leopold's maneuvers. This is important because a full bladder can displace the uterus, making it more difficult to accurately assess the fetal position and presentation during the maneuver. An empty bladder provides a clearer view and facilitates easier palpation of the fetus.

Other interventions, while they may be relevant in different contexts, do not specifically address the immediate needs when preparing for Leopold's maneuvers. Administering pain relief medication might not be necessary unless the client is experiencing discomfort that would impede the examination. Ensuring fetal heart tones are stable is typically assessed continuously but is not a preparatory step directly related to the maneuvers. Checking maternal vital signs is an important part of overall assessment, but it is not an essential step specifically required prior to conducting Leopold's maneuvers.