What Causes Spotting?

im a 28 female with PCOS i have 2 children and really rarely i have a period just yesturday i gad a gush of orange redish blood not much and didnt last for more than a hour im sexually active w no birthcontrol what so ever im 180 lbs im 5feet 2 inch and hadn had a period since after having a c section in dec 2009 should i be concerned?