Answer:
Before a client undergoes amniocentesis, the priority nursing intervention is to obtain informed consent from the client. This involves explaining the procedure, its risks and benefits, and obtaining the client's signature on a consent form. The nurse should also assess the client's understanding of the procedure and answer any questions or concerns they may have. Additionally, it is important to ensure that the client has a full bladder before the procedure, as this can help to move the uterus into a more accessible position and reduce the risk of injury during the procedure.