The side effects of emergency contraceptives, whether the contraceptive is in pill form or an intrauterine device, are generally mild and not long lasting. Nausea and vomiting, fatigue, and abdominal pain are commonly experienced. In the case of vomiting, the woman might have to retake a pill to ensure that the whole pill completely metabolizes. Other side effects may include vaginal bleeding comparable to that of a menstrual bleeding, a late period, or mild headaches. All of these effects should diminish and disappear within a few days, but a doctor should be consulted if the side effects become severe or if they do not go away.
One of the most common side effects of emergency contraceptives in pill form, also known as morning after pills, is nausea. Sometimes nausea is followed by vomiting that makes it necessary to take another dose of the emergency contraceptive pill. Over-the-counter nausea medicines, prescription-strength nausea medicines, or ginger tea might be recommended by a health professional if the nausea persists.
Some women also experienced mild headaches while taking emergency contraceptive pills. Like other side effects of emergency contraceptives, these headaches should diminish and disappear within two to three days. If they do not, a health professional should be consulted to ensure that everything is well.
If the emergency contraceptive used is an intrauterine device, the most common side effects are pain and discomfort and heavier menstrual periods. Menstrual bleeding can increase by up to 50 percent and become more painful, and is reportedly the most common reason women opt to have the device removed. While intrauterine devices are a more effective form of emergency contraceptive and can prevent pregnancy up to seven days after having unsafe sex, they also have the most potential to cause long-term discomfort if not removed.
Common side effects of emergency contraceptives that occur when taken in any form include abdominal pain and cramping. The pain and cramping might be similar to a menstrual period or much more severe, depending on the woman. A doctor might be able to prescribe a pain reliever to help manage the pain until it fades.
While both forms of these emergency contraceptives are usually very effective at preventing pregnancy, contraceptive pills are less effective if used more than once. The side effects may also be different if the pills are taken again later. If not removed, intrauterine devices remain an effective birth control for up to 10 years, depending on the type and assuming it is not expelled.