Emergency contraception: How to avoid pregnancy after sex

    Types of emergency contraception include the morning after pill and IUD
    Updated 27 February 2024 |
    Published 09 January 2020
    Fact Checked
    Medically reviewed by UNFPA, the United Nations sexual and reproductive health agency
    Written by Kate Hollowood
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    Did you know that emergency contraception can stop you from getting pregnant for up to five days after you’ve had sex? Get the lowdown on what emergency contraception is and how to access it with advice from a Flo expert.

    Whether you accidentally forgot to take your pill one day, a condom broke during sex, or you got too caught up in the moment, it’s entirely possible to have unprotected sex without meaning to. Things don’t always go to plan. 

    If you don’t want to become pregnant, this can be pretty anxiety inducing, but try not to panic. In the days following unprotected sex, there are still ways to avoid pregnancy

    It’s estimated that around 23.5% of women in the United States have accessed emergency contraception during their lifetime for one reason or another, so you’re definitely not alone. 

    Once you know the next steps to take, it can help you feel calmer. So, let’s look at your options so you can choose the best course of action for you.

    All your birth control choices explained

    How to avoid pregnancy after sex

    Emergency contraception can prevent up to 95% of pregnancies if you take it within five days after unprotected sex. There are two key forms of emergency contraception, which we’ll explore in more detail: 

    • The emergency contraceptive pill (ECP or “morning-after” pill): Depending on the type of pill you choose, you can take an ECP either up to three days after unprotected sex or five days. 
    • An intrauterine device (IUD or coil), which you’ll need to have inserted up to five days after unprotected sex

    It’s worth noting that while these methods may prevent you from becoming pregnant, they can’t protect you from sexually transmitted infections. If you’ve had sex without a condom with someone new, it’s always a good idea to book an appointment with your health care provider for a sexual health screening. 

    Is emergency contraception the same as abortion?

    It’s a common misconception, but emergency contraception is not the same as an abortion. While they might sound similar, the way emergency contraception works is actually very different

    “Emergency contraception prevents the egg and sperm from meeting (fertilization), while an abortion is conducted after fertilization or implantation have occurred,” says Flo expert Dr. Ruth Olumba, obstetrician, gynecologist, and gynecologic and cosmetic surgeon, Texas, US. 

    Sound confusing? Even if this is what you’re trying to avoid, it can help to understand what happens when you become pregnant. If you have sex, there’s a chance a sperm could meet with the egg released by one of your ovaries every cycle. It’s at this stage that emergency contraception steps in and prevents this from happening, by either preventing ovulation from happening in the first place or, if ovulation did happen, by preventing sperm from fertilizing the egg.

    If the sperm has already fertilized your egg, then it may travel down one of your uterine tubes and attach to the lining of your uterus. This is called implantation and officially marks the start of pregnancy. If you have an abortion, it ends the pregnancy after this point.

    How and when to take emergency contraception

    Depending on the country or state you live in and how much access you have to health care, you may not need to make a trip to the doctor’s office to access emergency contraception. You might be able to buy some types of ECP from local pharmacies, but that isn’t the case everywhere. If you can’t get one over the counter, you’ll need to get a prescription from your doctor. When it comes to the IUD, you can only get one from your health care provider

    Depending on the type of emergency contraception you opt for, the process of how and when to take it can be slightly different.


    The morning-after pill is a safe and reliable way to avoid pregnancy after unprotected sex when you take it correctly. There are three main types of ECP: 

    The first contains a synthetic hormone called levonorgestrel and is most effective when you take it within three days of having unprotected sex. Examples of brand names for this type of pill in the United States and United Kingdom are My Way, Next Choice, Plan B, Plan B One-Step, and Levonelle.  

    The second contains a drug called ulipristal acetate, and this can be taken up to five days after having unprotected sex. You might find this type of pill branded as ellaOne and Ella

    The third type is the combined emergency contraceptive pill, which you need to take in two doses as soon as possible up to five days after having unprotected sex. The number of pills you need to take may depend on the brand, so make sure you speak to your health care provider about the regimen you should follow. 

    All types of emergency contraceptive pills work by either stopping or delaying ovulation. “Without an egg, there is nothing for sperm to fertilize, therefore there is no pregnancy,” says Dr. Olumba. 

    Importantly, the sooner you take either type of ECP, the more effective it will be. It’s also worth knowing that the different types of ECPs have different rates of effectiveness. Ulipristal acetate-based pills have the lowest failure rate at 1% to 2%, meaning only 1 to 2 people in every 100 who use this type will get pregnant anyway. Meanwhile, levonorgestrel-based pills have a failure rate of 1% to 7%. The combined emergency contraceptive pill is the least effective of the three types.

    Copper IUD 

    A copper IUD is a form of regular contraception as well as emergency contraception. It’s a small device shaped like a T that a doctor puts inside your uterus. Copper IUDs are the most effective form of emergency contraception, preventing pregnancy 99% of the time

    To prevent pregnancy, the device needs to be inserted by your doctor up to five days after unprotected sex or, if you track your cycles, up to five days after ovulation

    So how do copper IUDs actually work? Well, they’re a little different from the morning-after pill, as they affect the sperm rather than ovulation. “The copper IUD prevents the sperm from fertilizing the egg by affecting the sperm’s health and function,” says Dr. Olumba. 

    A copper IUD is a great choice if you’re looking for a longer-term form of contraception, as once inserted, they can work for up to 10 years without any maintenance from you. So no more worrying about sticking to your birth control schedule

    If this sounds appealing, your doctor can help you decide if keeping the copper IUD is the right long-term contraception choice for you or whether switching to another type (like birth control pills) might suit you better. Check out our guide on when to start birth control for more information on choosing contraception. 

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    What are the side effects of emergency contraception?

    You might be worried that taking a new form of contraception after sex could leave you with some unwanted side effects. If you take the morning-after pill, there shouldn’t be any long-term side effects, but in the short term, you may experience: 

    • Headaches
    • Abdominal pain
    • Nausea or vomiting (if you vomit within two hours of taking an ECP, you’ll need to take another dose or get the copper IUD) 
    • Changes to your next period (emergency contraceptive pills can make your period come earlier or later or cause spotting between periods) 

    Meanwhile, one possible side effect of the copper IUD is painful and heavier periods in the first few months after having it inserted. These side effects should calm down within one year of using the copper IUD. 

    While side effects associated with contraception aren’t uncommon, you absolutely don’t have to deal with them alone. If you’ve had a copper IUD inserted or taken an ECP, and these symptoms don’t go away after a few days, contact your health care provider.

    Can you take emergency contraception more than once? 

    If you haven’t already found a form of birth control that really suits you, it could be a really good opportunity to look into the options after taking emergency contraception. You can take an ECP more than once in a single cycle, and there is no limit to how many times you can take it in your lifetime. However, figuring out a method of birth control that works for you could give you more peace of mind. Using regular birth control is also more effective at preventing pregnancy than relying on emergency contraception.  

    “Regular birth control is best, as emergency contraceptives result in higher total levels of hormones compared to ongoing use of birth control pills,” says Dr. Olumba. She explains that if you use an ECP regularly, it could also lead to side effects like irregular menstrual periods.

    What to do if you think you might be pregnant

    It can be tough to know what to do when you think you might be pregnant but aren’t quite sure. Try not to panic in this situation. Dr. Olumba explains, “Either take a pregnancy test at home or see your health provider or physician.” If you’re wondering what the early signs of pregnancy can be, try taking our pregnancy quiz

    If you’ve already booked your appointment with your health care provider for emergency contraception but now suspect you might be pregnant, keep your appointment. While the morning-after pill and copper IUD can’t be used if you’re already pregnant, your health care provider will be able to talk you through your options and may do a test with you at their office. 

    Becoming pregnant if you were trying to avoid it can understandably trigger difficult feelings. But with no contraceptive method being 100% effective, the chance of pregnancy even from protected sex is never zero. That means that if it happens to you, you’re not alone. There is a lot of support you can access to help you process your feelings — some of which may be conflicting — before you choose your route forward. Speak to your doctor too. They are there to support you and talk through your options.

    Content created in association with UNFPA, the United Nations sexual and reproductive health agency.


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    History of updates

    Current version (27 February 2024)

    Medically reviewed by UNFPA, the United Nations sexual and reproductive health agency
    Written by Kate Hollowood

    Published (09 January 2020)

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