Sexual Health: Birth Control - Emergency contraception

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Emergency contraception

Emergency contraception can be used to prevent pregnancy after unprotected intercourse or the failure of another birth control method. Emergency contraceptive pills (morning after pills) can be used up to 100 hours (three to five days) after unprotected sex, but the earlier they are used the better. A post-coital IUD can also be inserted to prevent pregnancy. This can be done up five to seven days after unprotected sex. Neither of these methods helps protect you against sexually transmitted infections.

Emergency Contraceptive Pills (ECP)

Emergency contraceptive pills may contain estrogen and progestin, or progestin alone. These are the same hormonal drugs contained in some birth control pills but at a different dose. When used for emergency contraception, these hormones interfere with ovulation to prevent a pregnancy. They may also change the lining of the uterus so a fertilized egg won't develop. These pills are not perfect, but they cut the risk of pregnancy by 75 to 85 percent.

Emergency contraception (ECP) is now available without a doctor’s prescription across Canada. A drug called Plan B, Canada’s only approved emergency contraceptive, can be obtained from pharmacists over the counter.

ECP is very safe. There is no evidence that these drugs cause harm to a pregnancy if they fail. You should not take the pills if you think you are already pregnant; they will not end a pregnancy that is already established.

Using the Pills

ECP is taken in two doses. Take the first dose as soon as possible after unprotected intercourse and the second dose 12 hours later. Or, alternatively, both pills can be taken together. This option does not change the effectiveness, but may be more convenient.

If you have purchased the medication in advance, check the expiry date to make sure the pills are still good. ECP will not prevent a pregnancy from sex that happens after you take the pills, or that occurred more than 100 hours before.

ECP can make you throw up or feel nauseous. If you throw up within one hour of taking your dose of ECP, contact your pharmacy about getting another dose. To reduce nausea:

try to eat something before taking the pills
take a Gravol or other over-the-counter anti-nausea drug before the second set of pills
take the pills with milk not water
If your nausea is severe, your doctor may be able to prescribe a stronger anti-nausea drug.

Other possible side effects of ECP include:

spotting
cramping
fatigue
breast tenderness

Your next period will likely be on time, but it may be early or late. If you don't have your period within three weeks of taking the ECP, visit your doctor or a pharmacy to have a pregnancy test done.

Emergency contraceptive pills are an emergency method used to cut the risk of pregnancy at one point in time. They should not be used as an ongoing method of birth control, but are effective as a back-up to other methods such as barriers or fertility awareness methods.

Post-coital IUD

A post-coital IUD is also a very effective way of preventing pregnancy after unprotected sex. It is the same as a regular IUD and can be used from five to seven days after intercourse. A post-coital IUD should not be used if a woman is also at risk of developing a sexually transmitted illness due to unprotected intercourse. Inserting an IUD when a woman has an infection can have serious complications.

Information on obtaining emergency contraception can be found by calling the AIDS and Sexual Health Info line at: 1-800-668-2437. In Toronto, you can visit our program at the Bay Centre for Birth Control.

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Last Updated: April 2009