Breakthrough bleeing is bleeding while taking the active pills of combined oral contraceptives, or other hormonal contraceptives. The bleeding is usually light, often referred to as "spotting," though a few women may experience heavier bleeding. Breakthrough bleeding is most common when a woman first begins taking oral contraceptives, or changes from one particular oral contraceptive to another, though it is possible for breakthrough bleeding to happen at any time. Smokers are especially prone to breakthrough bleeding while taking oral contraceptives; though many users experience breakthrough bleeding in the first three cycles of taking the pill, non-smokers tend to see the bleeding dissipate more quickly than smokers.