Final answer:
Fetal bradycardia can be caused by maternal hypotension, which may result from exercise. The nurse should monitor the patient closely.
Step-by-step explanation:
Fetal bradycardia, or a slow fetal heart rate, can be caused by various factors including maternal hypertension, maternal hypotension, maternal hyperthyroidism, and maternal hypothyroidism. In this case, since the patient exercises daily for three hours, it is possible that maternal hypotension may have resulted in the development of fetal bradycardia. Maternal hypotension, or low blood pressure, can reduce the blood flow to the fetus and affect its heart rate. It is important for the nurse to monitor the patient closely and consult with the healthcare provider for further evaluation and management.