Final answer:
The most appropriate nursing action is to continue monitoring the fetal heart rate.
Step-by-step explanation:
Each contraction sharply reduces oxygenated blood flow to the fetus. For this reason, it is critical that a period of relaxation occur after each contraction. Fetal distress, measured as a sustained decrease or increase in the fetal heart rate, can result from severe contractions that are too powerful or lengthy for oxygenated blood to be restored to the fetus. In this case, since the fetal heart rate is 100 beats/minute between contractions, it is within the normal range and does not indicate fetal distress.
Therefore, the most appropriate nursing action in this situation would be to continue monitoring the fetal heart rate to ensure that it remains stable and within the normal range. This will provide important information about the well-being of the fetus during labor and help identify any signs of distress.