Hi, Thanks for posting in HCM. I understand your concern. Next Choice is a single dose emergency contraceptive pill containing levonorgesterol. It would reduce the chances of pregnancy if it is taken within 72 hours (3 days) of having unprotected sex or a birth control failure. It works mainly by stopping the release of an egg from the ovary and may also work by preventing fertilization of an egg or by preventing implantation to the uterus. Thus, it should cause breakthrough bleeding within 3 weeks from the day of intake of the pill. Well, in your case, what you are experiencing is nothing but breakthrough bleeding. Bleeding could be sometimes brownish and red in color and might continue for a little longer than usual. This could happen because of the delay or slowness in shedding of the uterine lining (endometrium). Hence, you need not worry much about it. The next period should come normally and in time. Hope the information provided would be helpful. All the best.