Minor Side Effects

• Minor side effects of the morning after pill may include abdominal pain, breast tenderness, diarrhea, dizziness, fatigue, headache and nausea.
  
  

Menstrual Side Effects

• The timing or heaviness of your next period may be affected. Menstruation may be lighter, heavier or delayed after taking the morning after pill.
  
  

Serious Side Effects

• The morning after pill can change blood sugar levels, which is potentially dangerous to diabetics. Severe abdominal pain is considered a serious side effect and may be an indication of ectopic pregnancy.
  
  

Ectopic Pregnancy

• Ectopic pregnancies occur when a fertilized egg attaches outside of the uterus. If the morning after pill fails to prevent pregnancy, ectopic pregnancy is possible.
  
  

Time Frame

• Because the hormones from the morning after pill are in your system for less time than traditional oral contraceptives, there are fewer long-term side effects. The morning after pill is not recommended as a regular contraceptive method.