What are the differences between chronic and acute chorioamnionitis?

Not sure. Chorioamnionitis occurs in 1-4% of deliveries. I take care of infants born to mothers with this condition and give them antibiotics for at least 2 days until I know they are not infected. Most do just fine and are not infected. The pathologist may see inflammation of varying degrees under the microscope, but that has poor correlation with actual infection of the newborn.