Emergency Contraceptive Pills (ECP)

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What is ECP?

Unlike other birth control methods, ECP is medication you can take to prevent pregnancy after you have had unprotected intercourse for whatever reason, including sexual assault.

ECP is also known as the “morning-after pill” even though you can take it up to five days after unprotected intercourse.

There are two ECPs available in Canada: Plan B® and NorLevo®. They both contain a hormone called levonorgestrel, the formulation recommended by the World Health Organization.

How does ECP work?

It is not clear exactly how ECP works. Depending on the day in your menstrual cycle, it either delays or prevents the release of an egg (ovum), or it may work by preventing the implantation of a fertilized egg. 

Note that if you are already pregnant, taking ECP will not end your pregnancy.

How effective is it?

You can take ECP up to five days after unprotected intercourse. The sooner you take it, the better it works.

ECP will prevent pregnancy:

  • 95% of the time when taken within 24 hours
  • 85% of the time when taken within 25 - 48 hours
  • 58% of the time when taken within 49 -72 hours 

Two pills contain one full dose of ECP. You can take them both at once (1.5 mg.) or take two doses of 0.75 mg. twelve hours apart. Some research shows it is more effective to take both pills at once. 

Recent evidence shows that ECP is less effective in women over 165 Ibs. An IUD may be a solution and is not dependent on weight to be effective.

What are the advantages?

  • ECP is a back-up method if no method of birth control was used or if a method failed (missed pill, broken condom).
  • Most women do not have side effects.
  • Studies have shown no harm to the fetus if you are already pregnant.

What are the disadvantages?

  • ECP does not protect against sexually transmitted infections.
  • ECP may cause nausea or vomiting, changes in your next period or other minor side effects (see the information in the pill package). 

How do I use ECP?

  • Check the date in your cycle when you had unprotected intercourse. You can take ECP any time during your cycle; but the likelihood of conception is low the week before your next period. Learn more about fertility awareness here.
  • There are two pills. The sooner you take ECP, the more likely it is you will prevent an unplanned pregnancy. You may take both at once or 12 hours apart.
  • If you vomit within one hour of taking ECP, you may need to take it again. 

How do I know if my ECP worked?

You should get your period within three weeks of taking ECP. Your next period may come earlier, later or appear different than usual. 

If you do not get your period within three weeks, take a pregnancy test.

What should I think about before I take ECP?

  • Before taking ECP, it is good to consider whether you are already pregnant. If your last period was unusual or if your period is late, take a pregnancy test before taking ECP. 
  • ECP is not intended to be a regular form of birth control because it is less effective than other methods.
  • If you have had unprotected sex, you are at risk for sexually transmitted infections (STIs). Talk to your health care provider about STI testing. 

How can I get ECP?

You can get ECP at community health clinics, walk-in clinics and family doctors’ offices. It is also available at pharmacies over the counter (without a prescription).

Is there any other type of emergency contraception? 

A health care provider can insert an intrauterine device (IUD) within seven days of unprotected intercourse.

Where can I find more information?

Adapted from Women’s Health Clinic September 2013. Last update December 2013.

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