Birth Control

How Effective Is the Morning After Pill?

Key Takeaways

When it comes to contraception, knowing you’re protected when you need it is one of the most important parts of maintaining your peace of mind.

However, whether you’re lost in the heat of the moment, forgot to take your birth control pills, left the condoms at home, or ended up having some very unexpected fun, at some point, you may need to rely on some form of emergency contraception, like the morning after pill.

If you’re going to rely on this pill to prevent you from getting pregnant, you’ll want to know some more about it. Thankfully, the Felix Team has put together some useful info for you about what the morning after pill is, how it works, and how effective it is at providing you with protection.

What is the Morning After Pill?

The morning after pill could actually be a number of different medications, each of which functions by preventing or delaying ovulation.

They do this through a combination of both estrogen and progestin.

Estrogen is a natural hormone that plays an important role in both the sexual and reproductive health of people assigned female at birth.

On the other hand, progestin is a class of synthetic hormone that mimics the endogenous hormone from progesterone.

If you want to learn more about birth control options available to you through Felix, complete an online assessment. One of our experts will be able to answer any other questions you may have.

How Effective is the Morning After Pill at Preventing Pregnancy?

The morning after pill can be up to 97-99% effective, when it’s taken within the ideal time frame, and depending on each individual person’s likelihood of getting pregnant.

How Does the Morning After Pill Work?

Different ingredients in morning after pills have different effects for preventing pregnancy.


Levonorgestrel prevents ovulation by blocking the luteinizing hormone surge, which prevents the egg from being released.

Ulipristal Acetate:

Ulipristal acetate delays ovulation in the pre-ovulatory period, as well as after the LH surge has started.


Mifepristone prevents ovulation through the binding to progesterone receptors, as well as blocking the effect of progesterone within the body.

If you’re curious about which ingredients are in your chosen emergency contraceptive pills in Canada, ask your healthcare practitioner at Felix. They’ll be able to give you any additional information you need to make an informed decision about your contraception choice.

How Long After Sex Can You Take the Morning After Pill?

The best answer to this question is the sooner the better.

Ideally, you should take the morning after pill within 72 hrs of having unprotected sex.

Will the Morning After Pill Work if I Have Already Ovulated?

No, it won’t. However, most people don’t actually know when they’ve just ovulated, so you should take the morning after pill as soon as possible after unprotected sex.

If you are aware that you’ve already ovulated, you can still try IUD emergency contraception to reduce your chances of getting pregnant.

Are There Any Side Effects Associated with the Morning After Pill?

The most common side effects of the morning after pill are:

  • Headache
  • Abdominal pain
  • Nausea
  • Vomiting
  • Fatigue
  • Dizziness
  • Menstrual changes

The side effects of the morning after pill are typically not severe. If you start to experience severe side effects, be sure to talk to your healthcare practitioner at Felix. They may be able to suggest alternative medications that will work better for you.

What is the Cost of the Morning After Pill?

The morning after pill price can vary slightly, depending on which brand you’re using.

Typically, these pills cost less than $35 CAD each. Your healthcare practitioner will be able to give you a better idea of your pricing after your online assessment.

Are There Other Options for Emergency Contraception?

Yes, there is one alternative option.

If you’ve already ovulated, or your healthcare practitioner believes that the morning after pill may not be right for you (based on your health and medical history), you can use IUD emergency contraception.

This is 99% effective against preventing pregnancy, as long as you put it in within 5 days of having unprotected sex.

What Causes the Morning After Pill to Fail?

There are three major factors that can cause your morning after pill to fail:

1) Timing

Taking the morning after pill too late can drastically reduce its efficacy, so it’s important to take it as soon as possible.

2) Body Weight

People with a Body Mass Index (BMI) over 30 may not achieve the same level of efficacy from their morning after pill.

3) Malabsorptive Bariatric Surgery

This is a surgery that reduces the size of your stomach. It also limits the amount of nutrients the body absorbs, because the surgery causes your digestive tract to bypass a portion of your small intestine.

Because of this, serum LNG has been shown to be lower in patients that have had malabsorptive bariatric surgery, while UPA has not demonstrated any differences in clinical trials. In these cases, an IUD may be a likely option of emergency contraception.

Hopefully, you’ve learned everything you need to know about the morning after pill, and how effective it is. If you have any additional questions, don’t hesitate to talk to your healthcare practitioner at Felix.

They’ll be able to give you any guidance that you need to continue ensuring you’re protected against unwanted pregnancy, and so you can continue to embrace your sexuality in whatever ways make sense for you.

Medically reviewed by


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