Emergency Contraception: What You Need to Know

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on June 24, 2022.

What is an emergency contraceptive pill?

The emergency contraceptive pill is a safe and effective way to prevent pregnancy after unprotected sex, contraceptive failure or a sexual assault. Millions of women have safely used the emergency contraceptive pill and there have been no reports of serious complications or side effects. However, as with all drugs, there are directions for safe and effective use that must be followed.

• The emergency contraceptive pill is frequently referred to as “The Morning After Pill” but this is a misnomer, as women do not have to wait until the morning after sex to take the emergency contraceptive pill.
• Actually, the emergency contraceptive pill is more effective the sooner you take it -- as soon as possible after unprotected sex.
• It's a good idea to get emergency contraception before you need it, instead of waiting until after an accident happens. That way you can take it as soon as possible and don't have to hunt for a pharmacy or prescription.

The emergency contraceptive pill has also been referred to as the ‘abortion pill’, but the emergency contraceptive pill cannot cause an abortion if a woman is already pregnant. It is only effective if used before a pregnancy is established. Emergency contraceptive pills have no action to terminate an already established pregnancy.

Emergency contraception will not protect you from HIV infection (the virus that causes AIDS) and other sexually transmitted diseases (STDs). Use a condom if there is any chance of contracting a sexually transmitted infection.

Do I need the emergency contraceptive?

There are many valid reasons why emergency contraception may be needed. Some of these reasons include:

• You had unprotected vaginal sex in the last 5 days (120 hours).
• You used your regular form of birth control wrong, for example:
  • If you have a contraceptive failure, for example: a condom, a diaphragm, cervical cap, patch or barrier contraceptive broke, fell off, tore, or slipped.
  • If birth control pills, patches, rings or shots are started late or dislodged.
  • If a spermicidal contraceptive tablet fails to melt before sex.
  • If there is failed withdrawal ("pull out") during vaginal sex.
  • If your intrauterine device (IUD) or implant falls out.
  • If you take an oral "mini-pill" - a progestin only pill (POP) - and took your pill 3 hours late or more.
  • If you take a combination oral contraceptive (COC) estrogen / progestin pill and miss taking it by 2 days in a row or more.
  • You were a victim of sexual assault and forced to have sex when you did not want to.

How does the emergency contraceptive pill work?

Levonorgestrel, the medication found in Plan B One Step, Take Action, Next Choice One Dose, My Way and other levonorgestrel emergency contraceptive pills prevent pregnancy by stopping or delaying the release of the egg from the ovary (called ovulation). Emergency contraceptive pills may also change the lining of the uterus to prevent egg implantation or reduce the ability of the sperm to bind to an egg.

The levonorgestrel 1.5 mg emergency contraceptive pill should be taken within 72 hours after unprotected sex. It can lower your chance of getting pregnant by 75% to 89%, but it works best the sooner you take it.

How does weight affect emergency contraception?

The most effective choice for emergency contraception for overweight or obese women is the copper or hormonal (Liletta, Mirena) IUD with a 99% effectiveness rate. The copper IUD (a hormone-free option) is the other option. IUDs can then remain in place for up to 7 to 10 years as effective birth control. In addition, both types of IUDs work very well to prevent pregnancy regardless of body weight.

Some research suggests that levonorgestrel emergency contraceptive pills may not be fully effective in women who are overweight or obese, but this is controversial topic.

• Studies have found that overweight or obese women using emergency contraceptive pills may have a greater risk of pregnancy than women who are not overweight or obese.
• If you weigh 165 lbs (75 kg) or more, you might want to consider the Paragard IUD instead of emergency contraceptive pills for emergency use.
• Talk to your healthcare provider how weight might affect your use of emergency contraceptive pills.

IUDs for emergency contraception: See more below.

How does ella work?

Ulipristal, the progestin found in ella, works to prevent pregnancy by blocking the natural hormone progesterone from occupying its receptor site in the body. ella lowers your chances of getting pregnant by 85% if you take it within 5 days (120 hours) after unprotected sex, but works best if you take it as soon as possible.

Call a doctor or women's health clinic for a prescription or appointment quickly due to the 5 day limit.

• ella is more effective than the levonorgestrel emergency contraceptive pill, and can be used up to 5 days (120 hours) after unprotected sex; however, it requires a prescription.
• ella or the copper IUD may be a better option for emergency contraception in women if it has been more than 72 hours since unprotected sex.
• If you weigh 195 lbs (89 kg) or more, ella may not work as well for you. You may need to get an IUD emergency contraceptive.

After using Ella, you should use a reliable barrier birth control method (such as condom with spermicide) each time you have sex until your next menstrual period.

Wait at least 5 days after taking ella to resume regular contraceptive use (such as the pill, patch or vaginal ring) because they can lower the effectiveness of each other.

Do not use any additional levonorgestrel emergency contraceptive pills within 5 days after taking Ella.

Ella should not be used as your regular method of birth control. Contact a healthcare provider to discuss a form of ongoing birth control.

Can birth control pills be used for emergency contraception?

If you take combined birth control pills that contain both estrogen and progestin, and have no other options, higher doses can be used as an emergency contraceptive. They work by delaying ovulation, and the number of pills you would use for each brand of pill will differ between brands or generics. They don't work as well as other forms of emergency contraception but is better than no option at all.

A doctor, clinic nurse, or pharmacist can tell you how many pills you should take based on the type and brand of oral birth control that you use. Contact them immediately.

If you should miss your period by more than one week, take or get a pregnancy test.

Side effects with the emergency contraceptive pill

Emergency contraceptive pills are very safe to use. Side effects, if they occur at all, are usually short-term and mild.

Nausea has been reported in about 20% (20 out of 100) of women using levonorgestrel emergency contraception.

Vomiting may also occur in about 4% of women. If vomiting should occur within 3 hours of taking ulipristal (ella) or 2 hours of taking levonorgestrel emergency contraception (Plan B One Step and others), contact your doctor or pharmacist as a repeat dose may be needed. You may also need an anti-nausea medication.

Other side effects include:

• irregular bleeding, spotting, or heavier bleeding
• headache
• dizziness
• breast tenderness
• fatigue
• stomach pain

Women who normally cannot use combined birth control pills because of medical conditions such as migraines, heart or liver conditions, or breastfeeding can usually still use the emergency contraceptive pill as it is just a one-time dose. Ask your healthcare provider.

Does the emergency contraceptive pill end a pregnancy?

The emergency contraceptive pill will NOT stop an already established pregnancy.

Studies have shown that emergency contraception pill use does not increase the risk to the developing fetus in women who may already unknowingly be pregnant. However, the emergency contraceptive pill should not be taken by a woman who knows that she is pregnant.

Emergency contraceptive pills available in the US

In the U.S., the levonorgestrel emergency contraceptive pill can be obtained over-the-counter (OTC) without a prescription, an ID or age restriction. Levonorgestrel is the generic name of the progestin that is found in emergency contraceptives such as Plan B One Step and Next Choice One Dose.

Another emergency contraceptive pill, ella, which contains a different progestin called ulipristal is also available, but women must contact their physician as a prescription is required for ella.

Plan B and Next Choice, the original two-tablet regimens, are no longer marketed in the U.S. and have been replaced with Plan B One-Step and Next Choice One Dose, the one tablet levonorgestrel 1.5 mg regimen. Generic and more affordable options may be available, ask your pharmacist.

Learn more: Emergency Contraceptives Available in the U.S.

Can I take ella and my birth control pill on the same day?

No, after using ella if a woman wishes to use hormonal contraception (like the pill), she should do so no sooner than 5 days after using ella. After use of ella, a barrier method of contraception (such as a condom) should be used for sex that occurs in that same menstrual cycle.

ella and the progestin component of hormonal contraceptives both bind to the progesterone receptor, and using them together could reduce the effectiveness of each. Also, do not take ella with any other emergency contraceptive pill as it may also lower its effectiveness.

Can you use the IUD for emergency contraception?

Yes, certain IUDs (Paragard, Liletta, Mirena) can be used as emergency contraceptives, but they must be inserted by a health care provider within 5 days of unprotected sex but can be used as a long-term form of birth control after inserted. An IUD may be more costly up front, but your insurance or family planning clinic may be able to cover some or all of the costs for an IUD. Call your doctor or local women's health clinic as soon as possible for an appointment. Tell them why you need an appointment, since time is important.

An IUD is protective against pregnancy by more than 99% if you get it put in within 5 days of unprotected sex. The IUD form of birth control may also be a good long-term choice for women who would prefer not to take a pill every day. IUDs may work better in women who weigh more than 165 lbs (65 kg).

If you can’t get an appointment to have an IUD put in within 5 days after you have unprotected sex, take a morning-after pill like Plan B One Choice (available at a pharmacy) or ella (by prescription) as soon as possible. Call your doctor or pharmacist right away and ask for advice.

Copper IUD as emergency contraceptive

One option for emergency contraception is the insertion of the copper intrauterine device (IUD), also known as the ParaGard T 380A, up to 5 days after unprotected sex or a contraceptive failure. It is a hormone-free option. Overall, the copper IUD is the most effective form of emergency contraception -- over 99% effective.

The copper IUD is a T-shaped, hormone-free device that is inserted by a healthcare provider into the uterus to prevent pregnancy.

• The copper IUD works by making sperm less able to fertilize the women's egg or stops the egg from attaching to the wall of the uterus.
• The copper IUD can be left in place for 10 years for long-term birth control. It can be removed by your healthcare provider later if pregnancy is desired.
• If you need emergency contraception on the 4th or 5th day after unprotected sex, a copper IUD may be your most effective option.

Hormonal IUD as emergency contraceptive

Two brand names of hormonal IUDs that contain a progestin can also be used for emergency contraception -- Liletta or Mirena. It should be inserted within 5 days after unprotected sex or a contraceptive failure. These products both contain 52 mg of levonorgestrel.

IUDs that contain less than 52 mg of levonorgestrel, such as Kyleena and Skyla, should not be used as emergency contraceptives.

List of Common Emergency Contraceptive Options

How do I take the emergency contraceptive pill?

Plan B One-Step and other levonorgestrel 1.5 mg tablets, 1-pill version

• Plan B One Step, Next Choice One Dose, and others are available OTC as a single tablet of 1.5 mg of levonorgestrel. The manufacturer recommends the tablet in Plan B One-Step should be taken as soon as possible within 72 hours after unprotected sex.
• Generic and proprietary brands of levonorgestrel 1.5 mg tablet are available.
• Some studies have shown levonorgestrel 1.5 mg tablet can still be moderately effective up to 120 hours, or 5 days after unprotected sex. However, this may be dependent upon where you are in your ovulation cycle. As with all emergency contraceptive pills, they are more effective the sooner they are taken. Talk to your healthcare provider about this option.

ella

In addition to Plan B One Step, there is another type of emergency contraceptive pill called ella (ulipristal) that can also be used up to 5 days after unprotected sex.

• ella contains 30 mg of ulipristal, and it works to prevent pregnancy by blocking the natural hormone progesterone from occupying its receptor site in the body.
• ella lowers your chances of getting pregnant by 85% if you take it within 5 days after unprotected sex.

ella can be used up to 5 days after unprotected sex or a contraceptive failure but should be taken as soon as possible, as it is more effective the sooner it is taken. However, ella requires a prescription from your healthcare provider.

How often can I use the emergency contraceptive pill?

If unprotected sex should occur again, even within the same cycle, it is safe to use the levonorgestrel emergency contraceptive pill again if needed. However, a health care provider or clinic should be contacted as soon as possible so that a regular form of birth control can be started for ongoing contraceptive use.

Do not use ella (ulipristal) more than one time in the same menstrual cycle.

You should not use an emergency contraceptive pill as a regular method of birth control, because:

• It can be costly and inconvenient.
• It is not as effective as other options for birth control.
• It may expose you to higher total levels of hormones.
• It may lead to continued side effects, such as irregular periods, breast tenderness, or nausea.

If vomiting occurs within two hours of taking levonorgestrel emergency contraceptive or three hours of taking ella, you will need to repeat your dose. Contact your doctor.

Emergency contraceptive cost

Prices will vary, but in general the cash price (with discount coupon) of one regimen of over-the-counter levonorgestrel emergency contraceptive pill runs between $15 and $70 per package. Generics are typically less expensive, and you can ask your pharmacist if a lower cost option is available.

ella (ulipristal) also runs around $45 cash price, but remember it requires a prescription from your doctor. However, in many U.S. states, a pharmacist can give you a prescription for ella.

The copper IUD is expensive initially, but if continued as a long-term form of birth control, it can be very cost-effective. It is also convenient, as there is no need to remember to take a pill each day. The copper IUD can be left in place for up to ten years. Some insurance plans may pay for the IUD, as well. But if you are paying cash, the cost for an IUD, including insertion and office visit, typically runs between $500 and $1,300.

Learn More: Emergency Contraception Laid Bare: The 10 Biggest Myths Revealed

See also

• Birth Control Pills
• Birth Control Pills - Periods
• Birth Control Pills and Breakthrough Bleeding
• Birth Control Pills: Benefits, Risks and Side Effects
• Emergency Contraceptives Available in the U.S.
• Grapefruit and Birth Control Pills: Your Questions Answered
• Hormonal Birth Control (Non-Pill Options)
• Missed your birth control pill? Here's what to do
• Non-hormonal Birth Control
• Permanent Birth Control

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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