1. Side effects, too, were similar, with the exception of breakthrough bleeding . 2. Unexpected breakthrough bleeding can be a possible side effect of longer term active regimens. 3. Several combined hormonal contraceptives taken continuously, although this increases the risk of breakthrough bleeding . 4. Norethisterone acetate and medroxyprogesterone acetate may be used to artificially induce progestogen-associated breakthrough bleeding . 5. Estrogen also reduces the incidence of irregular breakthrough bleeding . 6. Breakthrough bleeding is likely due to hormonal fluctuations.7. "I didn't get any breakthrough bleeding that you can get when you start with the pill. 8. The pregnancies and increased incidence of breakthrough bleeding tipped off the real manufacturer, and the ring was broken up. 9. Side effects, too, were similar with the exception of breakthrough bleeding , which did decrease with each cycle of Seasonale use. 10. According to " Lange Gynecology and Obstetrics ", 8th edition, the most common side effect associated with OC use is breakthrough bleeding .