Final answer:
The first symptom of chorioamnionitis in the postpartum period is fever.
Step-by-step explanation:
The first symptom of chorioamnionitis in the postpartum period for a patient who had ruptured membranes for 72 hours before delivery is fever. Chorioamnionitis is an infection of the amniotic fluid and fetal membranes that occurs during labor. It is typically characterized by maternal fever, uterine tenderness, and an elevated maternal heart rate.