Plan B: What You Need to Know Before You Take It
When it comes to sexual health, knowing your options matters. One of the most common questions young adults ask is about Plan B, also known as the “morning-after pill.” It’s widely available, easy to get, and often talked about — but not always clearly explained.
This blog breaks down what Plan B is, how it works, its effectiveness, risks, and when to speak with a healthcare provider.
What Is Plan B?
Plan B is a type of emergency contraceptive pill you can get without a prescription at most pharmacies in Canada. It’s meant for one specific purpose: to help prevent pregnancy after unprotected sex or if your birth control didn’t work (for example, a condom broke).
It contains a hormone called levonorgestrel — the same hormone found in many regular birth control pills — but at a higher dose designed for emergency use.
How Does It Work?
- Plan B mainly works by temporarily stopping or delaying ovulation — which means it tries to prevent an egg from being released. If there’s no egg, sperm can’t fertilize anything, so pregnancy is less likely.
- It won’t work if you’re already pregnant, and it doesn’t affect an existing pregnancy.
- It also does not protect you from sexually transmitted and blood-borne infections (STBBIs) like chlamydia, gonorrhea, or HIV.
When Should You Take It?
Timing matters. The sooner you take Plan B after unprotected sex, the better:
- Within 24 hours = highest chance of working (about ~95% effective)
- Up to 72 hours (3 days) = still helps prevent many pregnancies
- It may still work up to 120 hours (5 days) but effectiveness drops as time goes on.
Important Things to Know
- Plan B Is for Emergencies — Not Regular Birth Control
- Plan B is not meant to replace regular contraception like the pill, patch, IUD, or condoms. Using it often isn’t the most effective way to prevent pregnancy and can make your cycle more unpredictable.
- If you’re sexually active often, talk to a health care provider about other options that would work best for you.
Side Effects and What to Expect
Most people don’t have serious problems, but Plan B can cause temporary side effects, such as:
• nausea or vomiting
• headaches
• dizziness
• abdominal cramps
• fatigue
• changes in your next period (it might come earlier or later than usual) These usually go away within a day or two.
If you throw up within 2 hours of taking the pill, you might need dosages redone — ask a pharmacist.
If Your Period Is Late
Your next period might be different after taking Plan B. But if your period is more than a week late, or you’re worried about pregnancy, consider taking a pregnancy test and talking to a health care provider.
Can It Cause an Ectopic Pregnancy?
Ectopic pregnancy (when a fertilized egg implants outside the uterus) is rare. Emergency contraception like Plan B does not cause an ectopic pregnancy — but if emergency contraception fails and you become pregnant, there’s a slightly higher chance the pregnancy could be ectopic, just like with normal pregnancies.
You should seek help right away if you have:
• severe pain on one side of your belly
• dizziness or fainting
• shoulder tip pain
• unusual bleeding
In Summary (Keep This in Mind)
• Plan B is emergency backup — not regular birth control.
• Take it right after unprotected sex (ideally within 24 hours).
• It won’t prevent STBBIs, and it doesn’t end a pregnancy.
• It can cause temporary side effects.
• You can get it in pharmacies without a prescription.
Want More Support?
At Mea Centre we support anyone facing an unexpected pregnancy, or possible pregnancy by offering free pregnancy tests, pregnancy options and sexual health information. If you are looking to avoid getting pregnant, one of our support workers can go through different options to help you find the right one for you. All our services are free and confidential. If you would like to book a private appointment click HERE.
You’re not alone — and understanding your options puts you in control.
By: Sarah, Client Services Director
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