Side Effects of Emergency Contraception

Emergency contraception is a birth control method to prevent pregnancy in women. Emergency contraception most likely works by preventing or delaying the release of an egg from a woman's ovaries. This method prevents pregnancy in the same way as regular birth control pills.

Most side effects of emergency contraception are mild. The mild side effects may include changes in menstrual bleeding, fatigue, headache and nausea. After using Plan B or Ella, your next menstrual cycle may start earlier or later than usual. It may also be heavier or lighter than usual. Most women get their next period within seven days of their usual date. If you are three weeks late, see a doctor.

Less common side effects of emergency contraception are diarrhea, migraines, vomiting, late periods, allergic reaction and severe abdominal pain. If you develop a skin rash, itchiness, swelling or labored breathing or wheezing, you should seek medical attention right away.

There are women who experience zero side effects and there are women who will experience all of them. About one quarter of women who take emergency contraception such as Plan B One-Step will experience nausea. Less than that will experience minor abdominal pain; similar to cramps. Of all side effects, you are least likely to experience a later than normal menstrual cycle.

Studies have shown that women who take emergency contraceptive in the first three weeks of their monthly menstrual cycles get their period much sooner than expected. The study also found that the earlier in their cycle women took the pills, the sooner they got their period.