Some women report bleeding and spotting a few days after taking their dose of Plan B, according to the University of Illinois. However, bleeding and spotting after taking the emergency contraceptive is not common.
Most commonly, women experience nausea after taking the emergency contraceptive Plan B, according to the University of Illinois. Other common side affects include cramping, dizziness, diarrhea, fatigue, moodiness and headache. Many women also experience subtle changes in their menstrual cycles following taking Plan B. The medication can cause women's periods to begin early, late, or be lighter or heavier than normal. However, women's menstrual cycles should return to normal the next month.