Having unprotected sex an hour ago carries a risk of pregnancy, but emergency contraceptive tablets can significantly reduce the chance if taken as early as possible. Medicines containing levonorgestrel are commonly used for emergency contraception and work best when taken within 24 hours, although they may still be effective up to 72 hours after intercourse. Another medicine, ulipristal, may also be prescribed in some cases and can work for a longer period. These tablets are meant only for emergency situations and should not replace regular contraception. Some women may experience nausea, tiredness, spotting, breast tenderness, or changes in the next period after taking the medicine. If vomiting occurs within a few hours after taking the tablet, another dose or medical advice may be needed. Please consult a doctor or pharmacist promptly for the correct tablet and dosage. Seek medical advice if your next period is delayed significantly or if you develop severe abdominal pain or heavy bleeding.