Original: After maintaining Category 5 status for about 12 hours, Ivan began a steady weakening trend due to another eyewall replacement cycle until reaching winds of 140 mph (225 km/h) on September 10.
Simplified: After maintaining Category 5 status for about 12 hours, Ivan began a steady weakening trend because of another eyewall replacement cycle until reaching winds of 140 mph (225 km/h) on September 10.