Emergency Contraception

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Emergency Contraception

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What is emergency contraception?

Emergency contraception is a way to prevent pregnancy if:

  • You had sex without using birth control.
  • Your birth control method failed. Maybe you forgot to take your pill or get your shot, the condom broke or came off, or your diaphragm slipped.
  • You were raped. Even if you were using birth control, emergency contraception can help decrease your chance of getting pregnant.

If you had sex without birth control, there is a chance that you could get pregnant. This is true even if you have not started having periods yet or you are getting close to menopause. You could also get pregnant if you used a birth control method that is not very reliable or if you didn't use it the right way.

Using emergency contraception right away can prevent an unwanted pregnancy and keep you from worrying while you wait for your next period to start.

What are the types of emergency contraception?

There are two types of emergency contraception: pills and the copper intrauterine device (IUD). Most women choose pills because they work well, don't cost a lot, and are usually easy to get. The IUD works very well, but it has to be inserted by a doctor.

Pills: Pills used for emergency contraception are sometimes called "morning-after pills." They can be used at any time up to 5 days after unprotected sex, but the sooner, the better. They contain hormones—either progestin only or a combination of estrogen and progestin.

  • Emergency contraception, such as Plan B or NorLevo, is a progestin-only pill that is packaged specially for use as emergency contraception. The cost of a single-use package is about $25 to $40.
  • Some birth control pills are also used. If you already take birth control pills, you may be able to use the pills you have as emergency contraception. Talk to your doctor or check the Web sites listed below for the correct doses.

IUD: The copper IUD is a small, T-shaped plastic device that is inserted into your uterus. The IUD is wrapped in copper, which helps kill sperm. It can be placed up to 5 to 7 days after unprotected sex to prevent pregnancy. (Note: The hormonal IUD, such as the Mirena, is not used for emergency contraception.)

  • Copper IUDs work very well but they may cost a lot—around $400 to $500. Provincial health plans usually cover the cost.
  • On the plus side, after a copper IUD is in place, it keeps working for up to 5 years.

An IUD is not a good idea if you have a pelvic infection or sexually transmitted infection (STI). An IUD could spread the infection and cause pelvic inflammatory disease, a serious health problem that can affect your ability to have children.

How does it work?

Emergency contraception pills work by preventing ovulation, fertilization, or implantation.

Emergency contraception hormones may prevent fertilization by stopping the ovary from releasing an egg (ovum). They also make the fallopian tubes less likely to move an egg toward the uterus. Emergency contraception is also thought to thin the lining of the uterus, or endometrium. The thickened endometrium is where a fertilized egg would normally implant and grow.

The copper IUD for emergency contraception may work by killing sperm, preventing fertilization, or preventing implantation.

Where can you get emergency contraception?

Emergency contraception. You can buy emergency contraception, such as Plan B or NorLevo, in most drugstores without a prescription.

Birth control pills. If you already have birth control pills on hand, you may be able to use them for emergency birth control. To find out which brands of pills work and how to take them, contact:

  • Your doctor.
  • The nearest public health unit or family planning centre.
  • The Canadian Federation for Sexual Health (CFSH) Web site at www.cfsh.ca.
  • The sexualityandu Web site at www.sexualityandu.ca
  • The Society of Obstetricians and Gynaecologists of Canada's (SOGC) emergency contraception information online at www.sogc.org/health/contraception-emergency_e.asp.

Some pharmacists will not sell emergency contraception or fill prescriptions for birth control pills. If this happens to you, ask for the location of a pharmacist who will, or go to:

  • The Canadian Federation for Sexual Health (CFSH) Web site at www.cfsh.ca.
  • The sexualityandu Web site at www.sexualityandu.ca

IUD. You can get an IUD from many doctors, from university and public health clinics, or in most hospital emergency rooms. An IUD has to be inserted by a doctor or other health professional.

How do you use it?

For the emergency contraception option that contains 2 pills (Plan B), you take both pills at the same time.

There is also a one-pill emergency contraception option (NorLevo) that lets you take the dose you need in just 1 pill.

For most regular birth control pills, you take one dose of 2 to 5 pills as soon as you can. Then you take a second dose 12 hours later. The dose depends on the type of pill.

You can take emergency contraception up to 5 days after unprotected sex. But it works best if you take it right away or within 48 hours.

If you use birth control pills for emergency contraception, keep the following in mind:

  • Birth control pills can cause nausea. Take an antinausea medicine such as Gravol with the first dose and again 1 hour before the second dose.
  • If you vomit within 2 hours of taking the pills, call your doctor for advice. You may need to repeat the dose.
  • Be sure you take the active hormone pills. In a 28-day pack, the first 21 pills contain hormones. The last 7 pills (the ones you take during your period) do not contain any hormones. If you use 21-day packs, all of the pills contain hormones.

A doctor or other health professional has to insert an IUD.

How well does it work?

Emergency contraception works very well. The sooner you use it, the more likely it is to prevent pregnancy. Overall:

  • Emergency contraception, such as Plan B, can prevent an average of about 74% of pregnancies.2
  • The copper IUD is more than 99% effective. Only about 2 women out of 1,000 who use it for emergency contraception will get pregnant.1

If you haven't started your period within 3 weeks after using emergency contraception, get a pregnancy test.

Does it cause side effects?

Emergency contraception may cause some side effects.

  • Emergency contraception may cause spotting or mild symptoms like those of birth control pills. It usually doesn't cause nausea.
  • Birth control pills can cause nausea or vomiting. In some women, they can also cause sore breasts, fatigue, headache, belly pain, or dizziness.
  • An IUD may cause cramping and bleeding during the first few days after insertion.

Call your doctor if you have a headache, dizziness, or belly pain that is severe or that lasts longer than 1 week.

If you are already pregnant, pills won't harm the fetus. An IUD could cause problems with the pregnancy.

What else should you think about?

  • Emergency contraception pills won't protect you for the rest of your cycle. Use your regular method of birth control, or use condoms.
  • Unless you get an IUD, emergency contraception does not take the place of regular birth control. Find a good method of birth control you can use every time you have sex.
  • Emergency contraception does not prevent sexually transmitted infections. If you are worried you might have been exposed to an STI, talk to your doctor.
  • Accidents can happen. It is a good idea to keep a set of the pills on hand in case you ever need it.

Other Places To Get Help


Canadian Federation for Sexual Health
1 Nicholas Street
Suite 430
Ottawa, ON  K1N 7B7
Phone: (613) 241-4474
Email: admin@cfsh.ca
Web Address: www.cfsh.ca

The Canadian Federation for Sexual Health, previously called Planned Parenthood Federation of Canada, is a non-government, pro-choice organization in Canada that provides services, information, and counselling exclusively on sexual and reproductive health.

Emergency Contraception Website
Phone: 1-888-NOT-2-LATE (1-888-668-2528)
Web Address: ec.princeton.edu

This Web site provides information about emergency contraception. This includes the correct use, effectiveness, and expected side effects of emergency contraception, along with how regular contraceptive pills can be used for emergency contraception. The Web site is operated by the Office of Population Research at Princeton University and by the Association of Reproductive Health Professionals.

A searchable database of emergency contraceptive providers in the United States is also available.

Web Address: www.sexualityandu.ca

The Web site gives teens, adults, parents, teachers, and health professionals information and education on sexual health.

World Health Organization Contraception Page
Avenue Appia 20
1211 Geneva 27, Switzerland  
Phone: +41 22 791 2111
Fax: +41 22 791 3111
Web Address: www.who.int/topics/contraception/en

This Web site of the World Health Organization (WHO) features links to related sites, fact sheets, and publications with information on contraception and family planning.



  1. Stewart F, et al. (2007). Emergency contraception. In RA Hatcher et al., eds., Contraceptive Technology, 19th ed., pp. 87–112. New York: Ardent Media.
  2. American College of Obstetricians and Gynecologists (2005, reaffirmed 2007). Emergency contraception. ACOG Practice Bulletin No. 69. Obstetrics and Gynecology, 106(6): 1443–1452.

Other Works Consulted

  • American Academy of Pediatrics (2005). Policy statement: Emergency contraception. Pediatrics, 116(4): 1026–1035.
  • American College of Obstetricians and Gynecologists (2005, reaffirmed 2007). Emergency contraception. ACOG Practice Bulletin No. 69. Obstetrics and Gynecology, 106(6): 1443–1452.
  • Stewart F, et al. (2007). Emergency contraception. In RA Hatcher et al., eds., Contraceptive Technology, 19th ed., pp. 87–112. New York: Ardent Media.


By Healthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Kirtly Jones, MD, MD - Obstetrics and Gynecology
Last Revised July 6, 2010

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