The “morning-after pill” is an emergency contraception which can prevent pregnancy after having sex without protection or if the birth control method used has failed. It has to be taken within 72 hours after contact; taking it earlier increases its effectivity. The pill works by delaying ovulation or interfering with fertilization. It contains levonorgestrel or ulipristal acetate. Levonorgestrel is an over the counter drug; its brands include Take Action, Next Choice One Dose, Aftera, Econtra EZ, Plan B One Step, and My Way. On the other hand, ulipristal acetate is only available with a prescription; its brand name is Ella. They are only used for backup as they are only around 89% effective. Probable side effects include headache, fatigue, dizziness, abdominal pain, vomiting, and breast tenderness.