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revised Friday March 11 2016
healthy sexuality
Birth Control Methods

Emergency Contraceptive Pill

Plan B is an emergency backup birth control method that contains a hormone called progestin.

Plan B prevents pregnancy by:

  • Stopping the ovaries from releasing an egg.
  • Blocking the sperm and egg from meeting.
  • Stopping a fertilized egg from attaching to the wall of the uterus.

How to Use Plan B

Generally women who can safely take the birth control pill can also use Plan B. Plan B comes in a pill form and can be accessed through a community pharmacy or one of Peel Public Health's Healthy Sexuality Clinics.

To prevent a pregnancy you must start Plan B within 72 hours after having unprotected intercourse.  The sooner you begin Plan B following unprotected vaginal sex, the more likely you will be able to avoid an unwanted pregnancy.

You should use Plan B if:

  • The condom broke or slipped.
  • You used withdrawal or no contraception at all.
  • You missed some birth control pills and didn't use a condom as backup protection.
  • Your Depo Provera injection was late (more than 13 weeks).
  • You applied your Patch late or it fell off.
  • Your diaphragm slipped.
  • You were sexually assaulted.
  • Your vaginal ring slipped out or you were late replacing your ring.


You will receive 1 pill in the package. Follow the package instructions carefully.

  • Eat a snack or meal (to decrease any nausea that may be felt).
  • Take the pill as soon as possible. It works best to take it within 12 hours of unprotected sex.

Side Effects

The most common side effect of Plan B is nausea, although very few women (only 6%) who take Plan B will actually vomit.

Taking Plan B with food will help reduce the nausea.

Other possible side effects, which are temporary and usually last only a few days, include:

  • mild abdominal pain
  • fatigue
  • headache
  • spotting or bleeding from the vagina

See a doctor immediately if you have itching all over your body or cramping or severe abdominal pain in your stomach or belly before your next period.



The sooner you take Plan B following unprotected vaginal sex the more effective it will be in preventing pregnancy. Plan B is approximately:

  • 95% effective if taken within 24 hours of unprotected vaginal sex.
  • 85% effective if taken within 25-48 hours of unprotected vaginal sex.
  • 58% effective if taken within 49-72 hours of unprotected vaginal sex.
  • Plan B is less effective in women weighing between 165 and 176 pounds (75-80 kg) and not effective in women weighing over 176 pounds (80 kg).
  • An IUD, inserted up to 7 days after unprotected sex, is recommended for women in this weight group

Advantages & Disadvantages



  • You can use it after intercourse.
  • You can use it with regular birth control pills.
  • You can get Plan B ahead of time in case you ever need to use it.
  • Plan B is simple to use.
  • Plan B doesn’t affect your ability to have children in the future.
  • You can get Plan B at a pharmacy without a prescription.
  • Doesn't protect you from sexually transmitted infections, including HIV/AIDS.
  • It’s only effective if you take it as soon as possible after unprotected vaginal sex up to 72 hours.
  • It can make you feel nauseous.
  • It must be readily available.

Cautions & Things to Consider

Plan B Doesn’t Protect Against STIs

Plan B won’t protect you or your partner from STIs including HIV/AIDS or Hepatitis B.  Use a condom every time you have sexual intercourse.

If You Vomit After Taking Plan B

  • If you vomit within two hours of taking the pill, call the clinic or doctor to see if you need another dose
  • If you vomited and saw the pill(s) in the vomit you need a replacement dose.
  • If you vomited more than 1.5 hours after taking Plan B you don't need a replacement dose.

Protection During the Rest of Your Cycle

Plan B won’t protect you from getting pregnant during the rest of your monthly cycle.

You must use another form of birth control, such as condoms, until you get your period. Your next menstrual period should begin at its expected time. Call for an appointment with your health care provider if it’s more than 1 week late or much different than normal.


Plan B is For Emergencies Only

You shouldn’t use Plan B as your regular method of birth control.

Speak to a health care professional about choosing a birth control method that’s right for you.

In certain situations, you may be offered Plan B to use at a later date.

If you get Plan B in advance, remember to:

  • Store it in a safe place away from children.
  • Check the expiry date before using it.
  • Follow the instructions carefully for taking it.

Plan B and Your Fertility

Plan B won’t affect your ability to get pregnant in the future.

Plan B and the Birth Control Pill

If you’re taking Plan B because you missed 1, 2 or 3 birth control pills, don’t take any of your missed pills. Take the Plan B doses then continue with the birth control pills left in your pack on the day after you take the second Plan B pill. Use condoms for at least the next 7 days.

If you’re taking Plan B because you missed 4 or more birth control pills, speak with a health professional about when to restart your birth control pills.

Contraceptive Patch

If the patch fell off or you were late changing the patch, take the ECP put on a new patch the next day. This will now be your new patch change day.

Contraceptive Ring

If the contraceptive ring was out for more than 3 hours:

  • take ECP
  • insert the ring the next day.

Taking Plan B If You’re Already Pregnant

Plan B won’t cause an abortion or harm the fetus if you’re already pregnant.

Get Tested for STIs

Since you’ve had unprotected sex, you should consider getting tested for sexually transmitted infections (STI), including HIV.


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Revised: Friday March 11 2016

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