I took plan b during my inactive birth control pills, im supposed to have my period but i only have brown discharge. does plan b mess with bc?

YES: It will cause you to have high levels of progesterone, which will prevent pregnancy; however, can cause prolonged menstrual bleeding.

Plan B One Step: will not interfere with oral contraceptives But it can impact bleeding. Potential side effects w emergency contraception include menstrual flow changes (spotting, bleeding, early or late period). Brown discharge is likely old blood being cleaned out of the uterus.