Final answer:
The nurse can expect an increase in heart rate when the FHR goes from 140 to 170 beats per minute. This can be due to factors like movement, stimuli, or changes in the mother's blood pressure or contractions.
Step-by-step explanation:
When the fetal heart rate (FHR) increases from 140 to 170 beats per minute, the nurse can expect this to be the result of an increase in heart rate. This increase in heart rate could be due to various factors such as exercise, stress, or changes in the external environment.
For example, if the fetus is moving or reacting to stimuli, it can lead to an increase in heart rate. Similarly, if the mother's blood pressure increases or she experiences contractions, it can affect the fetal heart rate.
Ultimately, the nurse should monitor the situation closely and consider any other accompanying symptoms or changes to determine the most likely cause of the increased FHR.