Ulipristal for Emergency Contraception

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Ulipristal for Emergency Contraception


Generic NameBrand Name
ulipristal acetate ella, ellaOne

Ulipristal is sold as "ella" in the Unites States and as "ellaOne" in Europe. It comes in a one-pill package (30 milligrams) that you can buy at most drugstores.

  • You need a prescription to buy ulipristal.
  • Females of any age can get a ulipristal prescription from a doctor. Girls don't need permission from their parents to ask a doctor for a prescription for emergency contraceptives.

How to take ulipristal

Emergency contraception is used after unprotected sex to prevent a pregnancy from starting. It's most effective when used as soon as possible after intercourse. Ulipristal is a new kind of pill that gives you more time after unprotected sex to take emergency contraception.

  • Contact your doctor's office as soon as possible after unprotected sex. It may take time to get a prescription for ulipristal or to find a pharmacy that carries it.
  • Take ulipristal as soon as possible. It can prevent pregnancy for up to 5 days after unprotected sex, but it works best if you take it right away.
  • Follow the directions on the package for taking the pill, or take it as your doctor tells you to.
  • Don't take ulipristal if you are pregnant.

How It Works

Ulipristal works by preventing or delaying ovulation. It won't protect you for the rest of your menstrual cycle. Continue to use your regular birth control method. And talk to your doctor about whether you need a backup method after you've taken ulipristal. If you don't have a regular method of birth control, talk to your doctor about starting one.

Ulipristal won't protect against sexually transmitted infections (STIs). If you're worried that you might have been exposed to an STI, talk to your doctor.

Ulipristal isn't your only choice. There are other emergency contraception methods and pills available, including some that don't require a prescription.

Why It Is Used

Emergency contraception is meant to be used as a backup method for preventing pregnancy. For regular protection, be sure that you have:

  • A birth control method that you know you can use every time you have sex.
  • Condoms for protection from sexually transmitted infections (STIs) every time you have sex.

You can use emergency contraception if you aren't confident that you were protected against pregnancy during intercourse. This can happen if:

  • You have unplanned sex without birth control.
  • Your usual birth control method fails. For example:
    • A barrier method, such as a condom or diaphragm, has torn or dislodged.
    • You have missed taking birth control pills.
    • An IUD has come out, either completely or partially.
  • You are taking other medicines that may affect contraception medicines. These include some anti-seizure and antifungal medicines, and the herb St. John's wort.
  • You were sexually assaulted. Some emergency rooms offer emergency contraception as part of sexual assault care. Others will provide emergency contraception when they are asked for it.

Be sure to plan with your doctor for your birth control needs.

How Well It Works

Ulipristal and the other emergency contraception pill, levonorgestrel (such as Next Choice or Plan B), work well when used soon after unprotected sex:

  • If you aren't able to take an emergency contraceptive within the first 3 days after having unprotected sex, ulipristal works better than levonorgestrel. It can prevent pregnancy for up to 5 days after unprotected sex.1
  • If you are able to take an emergency contraceptive within 3 three days of having unprotected sex, ulipristal works about the same as levonorgestrel.1 (Levonorgestrel has been shown to prevent about 3 out of every 4 pregnancies when used within 3 days of unprotected sex.)2

After you take ulipristal, your next period may start a few days earlier or later than expected. If your period is more than 7 days later than expected, or if it is lighter than expected, you should get a pregnancy test.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine. Usually, the benefits of the medicine are more important than any minor side effects.

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.

Call your doctor right away if:

  • Hives.
  • You vomit within 3 hours after taking the pill. You may need to take another one.
  • You have a headache, dizziness, or belly pain that is severe or lasts longer than 1 week.
  • You think you might be pregnant.

Common side effects of this medicine include:

  • Headache, upset stomach, or belly pain.
    • If needed, take an over-the-counter pain medicine such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve). Read and follow all instructions on the label.
    • For belly pain, use a hot water bottle or a heating pad set on low.
  • Light bleeding (spotting) in the week after you take the pill.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Some pharmacists refuse to fill emergency contraception prescriptions based on their personal beliefs. If this happens to you, ask for the location of a pharmacist who will fill the prescription, or:

  • See the Emergency Contraception website at http://ec.princeton.edu and click on "Get EC Now," or call 1-888-NOT-2-LATE (1-888-668-2528).
  • Visit the Planned Parenthood clinic nearest you at http://www.plannedparenthood.org/health-center/findCenter.asp, or call 1-800-230-PLAN (1-800-230-7526).

Since you need a prescription to buy ulipristal, your health insurance may cover the cost.

Birth control experts recommend having emergency contraception pills, or a prescription for them, on hand in case you ever need them. Throw away any pills that are past the expiration date. You can find the expiration date on or inside the package the pills come in.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

Related Information



  1. Glasier AF, et al. (2010) Ulipristal acetate versus levonorgestrel for emergency contraception: A randomised non-inferiority trial and meta-analysis. Lancet, 375(9714): 555–562.
  2. American College of Obstetricians and Gynecologists (2010). Emergency contraception. ACOG Practice Bulletin No. 112. Obstetrics and Gynecology, 115(5): 1100–1109.

Other Works Consulted

  • Emergency Contraception Website (2011). Types of emergency contraception: When would I use ella instead of Plan B One-Step or Next Choice? Available online: http://ec.princeton.edu/questions/ella-vs-levo.html.
  • Planned Parenthood (2011). Background on ulipristal acetate (ella): A new emergency contraception pill. Available online: http://www.plannedparenthood.org/files/PPFA/fact-ella-EC.pdf.


ByHealthwise Staff
Primary Medical ReviewerSarah Marshall, MD - Family Medicine
Specialist Medical ReviewerFemi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology
Last RevisedMay 4, 2012

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