Final answer:
The nurse should relieve pressure on the prolapsed umbilical cord to prevent compression and reduce the risk of hypoxia to the fetus.
Step-by-step explanation:
When a visible prolapse of the umbilical cord occurs after a client experiences spontaneous rupture of the membranes during labor, the nurse should implement immediate intervention by relieving pressure on the cord to prevent compression and reduce the risk of hypoxia (lack of oxygen) to the fetus. The nurse should instruct the client to assume a knee-chest or Trendelenburg position to relieve pressure on the cord. Additionally, the nurse should elevate the presenting part of the fetus using sterile gloved hand or a sterile towel to prevent further compression of the cord. These measures can help ensure sufficient blood supply and oxygen to the fetus until a more appropriate intervention, such as a C-section, can be performed.