Emergency contraception (EC)

What is emergency contraception?

EC is a way to help keep you from getting pregnant if you have sex without using birth control or if your birth control does not work correctly.

What are the types of EC?

There are 3 types of EC to choose from and they all work up to 5 days (120 hours) after unprotected sex. The sooner you use EC, the better it works.

Copper-T IUD

  • The ParaGard® copper IUD is the most effective EC there is.
  • A provider places the IUD in the woman’s uterus within 5 days of unprotected sex.
  • This IUD lowers the chance for pregnancy by 99% when put in for emergency contraception.
  • The copper IUD is also very effective birth control and can stay in place for up to 10 years.

The ulipristal acetate pill, Ella®

  • This is one pill that blocks the hormones your body needs to get pregnant.
  • It works well if taken within 5 days after sex.  Effectiveness does not change up to 5 days after unprotected sex.

Levonorgestrel pills, such as Plan B One-Step®

  • This is one pill that has a hormone found in birth control pills (levonorgestrel), but at a higher dose.
  • It can work up to 5 days after unprotected sex, but it does not work as well the longer you wait to take it.
  • It is best within 72 hours of unprotected sex.

How do I get EC?

It depends on the type of EC you need.

Copper-T IUD

The ParaGard® IUD must be put in by a provider. 


  • This can be prescribed by your provider or family planning clinic.
  • Please call your pharmacy to make sure they carry this medicine.

Plan B One-Step®

  • People of any age can get this in stores without a prescription. It is usually sold by a pharmacist or on the shelf near the pharmacy.
  • If you do not see it on the shelf, ask the pharmacist for help. There are a few pharmacies that do not carry this.
  • There are generic versions of this type of this EC also.
  • This is not an abortion pill.

How does EC keep me from getting pregnant?

The copper in the IUD is toxic to sperm so they die before they can get to an egg. It may also change the lining of the uterus to stop a pregnancy.

EC pills work by stopping or slowing down ovulation (when an egg leaves the ovary). If you are pregnant, EC pills will not stop or harm your pregnancy.

How well does EC work?

  • The Copper IUD prevents pregnancy 99.9% of the time. It works for all weight ranges.
  • EC pills prevent pregnancy less than 90% of the time.
  • Plan B One-Step® does not work as well if you weigh over 165 pounds.
  • Ella® is more effective than Plan B One-Step® in certain situations. Please talk with your provider.

What are the side effects of EC?

The Copper IUD may cause cramping and longer or heavier periods.

EC pills can cause sometimes cause nausea or a headache. They can also change the timing of your next period. It may come late or early.

Last reviewed: 
April 2020
Alternative Names: 
Morning after pill

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