Final answer:
The first action a nurse should take when a client's water breaks and the umbilical cord is noted on the perineum is to place the client in the Trendelenburg position to reduce pressure on the cord and avoid compression. The correct option is a.
Step-by-step explanation:
When a client in labor states, "I think my water just broke!" and the nurse notes that the umbilical cord is on the perineum, the initial action that the nurse should take is to place the client in Trendelenburg position.
This intervention is vital because it helps reduce the risk of umbilical cord compression, which could compromise the baby's oxygen supply. The Trendelenburg position, where the client is laid back with feet higher than the head, helps to relieve pressure on the cord until medical intervention can correct the prolapse.
Subsequent actions would likely include administering oxygen via face mask to ensure the mother is well-oxygenated, which in turn helps oxygenate the fetus, and notifying the operating room team in preparation for a potential emergency cesarean delivery if required.
Administering a fluid bolus may also be considered to support the mother's blood pressure and circulation, which can benefit fetal circulation, but this is not the first action to take in the case of umbilical cord presentation. Option a. is the correct one.