Emergency Contraception

Updated: 6 days ago


Emergency contraception (EC) is a method of birth control that is used up to 5 (ideally 3) days after unprotected sex to prevent pregnancy. EC pills do NOT protect against sexually transmitted diseases (STDs).


There are 2 types of EC pills:

  • Plan B One-Step (levonorgestrel) and its generics Next Choice, My Way, and Preventeza: progestin hormone; available over-the-counter or by prescription

  • Ella (ulipristal acetate): hormone blocker; available by prescription only


How does it work?

EC pills prevent pregnancy by delaying ovulation, the release of an egg. Track your cycle with a calendar to determine if you have ovulated yet (if you are close to your next period); if you have, EC pills may not work.


How well does it work?

Using EC lowers your risk of pregnancy by 58-94%, depending on what type of EC you use, how quickly you take it, your weight (no effect on the copper IUD), and where you are in your cycle. It can be taken up to 5 days after unprotected sex, but it works better the sooner you take it. In general, EC pills are not as effective as regular forms of birth control like the pill, patch, ring, shot, or IUD.


How do I take it?

Take EC as soon as possible after having sex that was unprotected or if you suspect your birth control did not work (recently missed pills, broken condom, etc.). If you throw up within 2 hours of taking an EC pill, take another dose. Anti-nausea medicine can be taken an hour before to prevent this from happening.


What should I NOT do?

  • Do not have unprotected sex after taking EC. You'll need another form of birth control for future sex.

  • Do not take the 2 different types of EC together. They might cancel each other out.

  • Do not use regular, hormonal birth control as emergency contraception.


What side effects might I experience?

Most people don't experience any side effects. Headache and nausea are possible. EC can also cause your period to come later than expected.


What if I want to get pregnant soon?

You can get pregnant right after taking an EC pill if you stop all other forms of birth control. If a pregnancy has already happened, EC pills will not harm the developing fetus or end the pregnancy.


See the table below to determine the best EC pill for you:

*The copper IUD can be used as EC if inserted within 5 days of unprotected sex. It is more effective than the pill options, regardless of your weight.


Updated August 2020

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