Final answer:
The priority nursing action when late decelerations of the fetal heart rate are observed during labor is to change the client's position to potentially improve placental blood flow and fetal oxygenation.
Step-by-step explanation:
When the fetal heart rate begins to decelerate after the contraction has started and the lowest point of deceleration occurs after the peak of the contraction, this is often indicative of late decelerations, which can be a sign of fetal stress due to uteroplacental insufficiency. The priority nursing action in such a situation should be to improve fetal oxygenation.
The recommended initial action would be d. Change the client's position. This can help to improve placental blood flow and increase oxygen delivery to the fetus. The other options, such as preparing for amnioinfusion, inserting a scalp electrode, or documenting benign decelerations, may be considered if the decelerations are persistent or if there is evidence that they are not benign.